109.05 Payment for Contract Revisions
See Section 103.02 Contract Revisions for information regarding payment for Contract Revisions.
Title 23 Code of Federal Regulations (CFR) 635.120, titled Changes and Extra Work requires that MDOT performs and adequately documents a cost analysis of each negotiated contract change. Payment is to be based on the following methods detailed in Subsection 109.05 of the Standard Specifications for Construction:
The Engineer will first attempt to price revised work using contract unit prices/items of work. This justification is based on similar work and pay items in the existing contract.
If contract unit prices will not work, then per 109.05.C then the Contractor and Engineer will negotiate the price of a contract revision. When using negotiated unit prices the analysis, justification and documentation should include all applicable information from the following:
- Comparison with actual unit prices on other projects in the geographical areas, weighted average unit prices and/or historical prices for similar work.
- Engineer should compare to similar units of work on the project or similar items of work on other projects.
- Consider impacts of scale/small quantities on unit prices as smaller quantities tend to have higher prices.
- Consider any unique factors affecting unit prices (mobilization, mobility, work zones, expedited schedules, etc.) and their potential impact upon unit prices.
- Cost analysis based on planned materials, labor and equipment to be used for the work.
- The Contractor must provide the detailed estimate of costs within 5 calendar days of the Engineer’s request Per 109.05C
- Engineer should evaluate the Quantity of work to be completed; equipment required to complete the work, materials, mobilization, and other items detailed in the Contractor’s estimate. Also consider the impacts of other factors such as weather impacts, staging issues, mobility restrictions, scheduling issues, etc. which may impact pricing.
- Use of production rates, estimating manuals and/or national cost estimating publications can also be used to help support the cost analysis.
The preceding information and cost justification is to be noted in the reason section for extra work items on contract modifications and the supporting information placed in the project file..
After agreement is reached with the engineer and contractor on pricing the extra work from unit price or negotiated price methods, then the engineer should prepare a contract modification to document the agreement and begin the payment process per the guidance in Contract Modification Development.
When the previous two methods do not provide an agreement or any time work starts prior to a price being established, then force account procedures shall be used. The Work Plan and daily reconciliation forms are required any time work commenced prior to price being established. Furthermore, when work commences under the force account method but is then later negotiated by the engineer and contractor to be a lump sum item of work (pay item 1090003 Negotiated Force Account), the force account records under which work started must still be retained within the project files.
Force accounts are a tool the engineer may use to compensate the contractor for the performance of extra work at actual costs incurred plus additional markups as detailed in the 2012 Standard Specifications for Construction subsection 109.05. Force accounts are to be used only in rare circumstances where the contractor and engineer cannot agree on a price, the scope of work cannot reasonably be determined, or other payment methods for compensation are impractical. Prior to commencing force account work the Region Construction Engineer must approve the additional work (Approval can be documented on an IDR or an e-mail).
A work plan must be developed prior to commencing force account work. The work plan development begins with the contractor's required submission of a documented proposal for the extra work per subsection 109.05. This proposal is reviewed by the engineer, then the contractor and engineer will collaborate to develop a work plan from the contractor’s documented proposal. The work plan can vary in length/detail depending upon the scope of work to be accomplished. This may range from a brief email for small/short duration force accounts accomplished in a few hours to more extensive multi-page work plans for complex, longer duration force accounts. The work plan should address at a minimum each of the following items listed below:
- General description of work to be performed.
- Schedule - show detailed activities, durations, constraints, and any other relevant information including activities of subcontractors and specialty contractors. Provide an updated project schedule and/or documented narrative noting any possible impacts to the approved project schedule and controlling items of work.
- Labor – Provide the number of people/classifications/crafts of contractor/subcontractor personnel, estimated work hours, and any special considerations including any overtime, night work, or any other work anticipated to take place outside of established project work hours etc.
- Equipment – Provide a list of all contractor owned, rented and/or leased equipment, including custom or special equipment in the work plan for engineer approval.
- Materials – Provide a detailed listing of all materials incorporated into the finished work required to complete the force account work.
- Misc. Items - Include any other relevant aspects or constraints to the work, such as purchase orders for services, disposal fees, freight/transport costs, etc. Temporary sheeting and other items not permanently incorporated into the finished work are not considered materials, thus, not eligible for the 15% materials mark-up
- Estimated total cost - Include a detailed breakdown of all anticipated items and their estimated costs. This may be used as the basis of a budgetary contract modification for longer duration force accounts in order to make progress payments.
- Designation of the contractor’s representative with authority for signing the daily field record.
If the conditions relative to the force account change or if the progress of the work becomes inconsistent with the original work plan, the contractor and the engineer will collaboratively revise the documented work plan within one work day of notification of required change. Work plan revisions must be documented, but may be as simple as e-mail exchanges where both parties are in agreement. Items not contained in the approved work plan are ineligible for reimbursement. View a sample Force Account Work Plan through the link below.
Force Account Work Plan
After acceptance of the work plan by the engineer and prior to starting any force account work, the engineer will issue a work order (form 1137) directing the contractor to commence the force account work in accordance with the approved work plan attached to the work order. Any revisions to the work plan will be documented in a revised work order.
Final payment for force account work must be made by the engineer after the supporting documentation is reviewed and accepted. No payment will be made for any expense (i.e. rented equipment, taxes, and bond premiums) without proof of what the contractor paid unless specified otherwise. The engineer may generate a budgetary force account contract modification for bi-weekly progress payment purposes and make payments for any items that have all documentation submitted and approved. Bi-weekly progress payments should only be made after the contractor has signed off on all daily force account records for the time period being paid.
Bi-weekly budgetary force accounts payments will be based on estimated cost incurred and costs for which final documentation is available (certified payrolls, paid invoices, etc.). Final payment will be adjusted by the engineer after the final force account documentation is reviewed and accepted. The engineer is responsible for ensuring final payment covers only items identified in the approved work plan and proof of payment has been supplied by the contractor (i.e. rented equipment, taxes and bond premiums). In some instances, the contractor may not be able to provide proof of payment of items such as additional bond premiums until near the end of the project.
Force account work is fundamentally different from normal construction contract work as the engineer/owner has more responsibility to direct the work and insure the performance of the work is as efficient as possible. This can require more involvement in the direction of the work than would normally occur in typical contract work to give reasonable assurance that efficient methods and cost controls are being used. The work plan should address any unusual work hours or special considerations for the engineer to adjust inspection schedules to meet this requirement.
Once the force account work has started, the engineer has the responsibility to ensure that the work is progressing timely and efficiently as per the issued work order. If the engineer finds labor, equipment or materials on site that are not required for the completion of the force account work in accordance with the agreed upon work plan it is the responsibility of the engineer to revise the work plan as required or for the engineer to refuse payment for charges outside of the scope of the work plan. The engineer needs to remain diligent in monitoring work performed to ensure that the contractor is not being paid for contract pay items while at the same time charging their time, materials and/or equipment to the force account.
See Appendix A: How to fill out the Contractor's-Force Account Statement which is form 1101-SP109 for all projects let after October 7, 2016 or form 1101 for project let before October 7, 2016 and 1101A(Force Account Daily Field Record, which applies to both forms) for further guidance on what is required for field documentation of the force account by the engineer.
Subsection 109.05.D.11 requires the contractor to furnish form 1101 if let before October 7, 2016 or form 1101-SP109 if let after October 7, 2016, containing itemized statements of cost and copies of the weekly certified payroll. These documents must be reconciled with the daily force account statements.
The following guidelines were developed to assist in the preparation and checking of force accounts.
- Force accounts must be submitted on the Force Account Statement (form 1101-SP109).
- Attach any notes that may be required to explain rates and/or calculations.
- Supporting documentation for every cost/item included in the force account statement form 1101-SP109 is required for payment.
For projects let prior to October 7, 2016 the engineer will pay the contractor an amount equal to the sum of the actual on site labor costs plus 35 percent.
As of the October 7, 2016 all projects will contain the Special Provision for Force Account Mark-up for Bond Premium, Insurance, and Payroll Taxes (12SP-109C-01) requiring the engineer to pay the contractor an amount equal to the sum of the actual on site labor plus 55 percent for road work or 60 percent for bridge work. Costs for bonds, insurance, and taxes will no longer be reimbursed directly. The road or bridge markup is to be applied based on the actual nature of the force account work.
- Foreman exempt from prevailing wage requirements will receive the hourly rate agreed to in the work plan which must be confirmed by the submission of certified payrolls.
- Prevailing wage covered workers will receive the rate of wage (or scale) shown in the project wage determination or a higher rate as confirmed by the submission of certified payroll.
- The contractor will receive the amount paid to, or on behalf of workers for bona fide fringe benefits. This includes benefits required by a collective bargaining agreement or other employment contract generally applicable to prevailing wage covered workers and common to the construction industry. (NOTE: Generally vacation/holiday pay is considered taxable income; therefore, it should be included with the base labor rate to which the applicable mark-up percent is added.)
- Name, class, dates, and number of hours worked must be listed on form 1101. A job title cannot be used in lieu of an employee’s actual name for purposes of verification with certified payrolls.
- The contractor must submit certified payroll for all workers covered by the prevailing wage provisions of the contract as well as any other labor hours for which reimbursement is sought.
For superintendents, the amount the contractor will receive will be limited to the work hours in which the superintendent is actually engaged in the performance of the force account work. The department interprets this to mean; pay for superintendents will only be reimbursed for time spent on site of work engaged in the performance of covered work and at wage and fringe rates equivalent to the classification of work being performed, unless otherwise negotiated and documented in the approved work plan.
As of the October 7, 2016 letting, contractor incurred costs related to bond premium, insurance, and payroll taxes will no longer be reimbursed directly if the Special Provision for Force Account Mark-Up for Bond Premium, Insurance and Payroll Taxes is in the contract documents. This special provision provides an enhanced markup to the labor rates for these costs. In the interest of expediting project delivery and alleviating administrative burden, the department has increased the mark-up on labor costs in lieu of compensating contractors for bond premium, insurance, and payroll taxes as defined in 109.05.D.4. The correct form for this is 1101-SP109.
Projects that do not have the Special Provision for Force Account Mark-up for Bond Premium, Insurance and Payroll Taxes should use the following methods for reviewing these direct costs. The correct spreadsheet is 1101 which is linked here
Contractor incurred costs related to bond premium, insurances and payroll taxes will be reimbursed at actual cost plus an 11% markup. Per subsection 109.05.D.4 “The contractor must furnish satisfactory evidence of the amounts actually paid for each of these required costs as related to force account work.” Additional guidance on the minimum acceptable documentation to establish satisfactory evidence of the costs actually being paid is detailed below for each item:
The original bond policy required in the contract documents for a project may cover the force account work without additional costs incurred by the contractor. However, there are circumstances where the contractor may incur additional bonding costs including; the purchase of a policy rider or amendment specifically for the force account work or for contractors that pay bonding as a percentage of final project cost (project amount). Only costs actually incurred by the contractor will be reimbursed after receiving proof of payment. The required documentation for proof of payment is:
- A copy of the bond policy or contract addendum to an existing bond policy specifically for the force account work.
- A comprehensive reconciliation of the total bond contract billing adjusting for all extra work additions and pay item deletions from the covered amount of the bond contract. Reconciliation must detail the precise impacts only attributable to the force account work on the project. Documentation must also be provided to satisfy the requirements of subsection 109.05.D.4. Any other costs or bond contract impacts not directly attributable to the force account work are to be considered regular business overhead expenses and not eligible for reimbursement under subsection 109.05.D.4 unless the costs can be both attributed directly to the force account work and proof of payment can be provided.
Workman’s Compensation Insurance
Workman’s compensation insurance is a cost that all construction contractors incur per the requirements of 107.10 and the contractor may incur additional costs for workman’s compensation insurance for labor hours on force account work. Workman’s compensation rates vary for every company and worker classification. Only costs actually incurred by the contractor will be reimbursed. The required documentation for proof of payment is:
- A statement from the provider of the workman’s compensation insurance with the percentage rate that the contractor is charged on straight time hours for each worker classification type.
- Since workman’s compensation insurance rates are partially based on the risk of the job duties, each worker classification typically has a different rate. The contractor will need to provide a breakdown for each employee of actual time spent performing each classification of work. The total hours of each classification type (all carpenters, all laborers, etc.) must be totaled and a reimbursement calculated using the percentage rates obtained from the workman’s compensation insurance statement.
Personal Injury Public Liability and Property Damage Public Liability Insurance
Per 107.10 the contractor is required to purchase public liability insurance for both personal injury and property damage in order to bid work on any MDOT project. These standing insurance policies are required to have each project the contractor works on added to the policy coverage as a named insured party. No other types of liability insurance are listed as eligible for reimbursement in 109.05D4.
There is typically not a relationship between awarded cost vs final project costs with respect to these public liability insurance policies, however, if the contractor has a policy based on final contract amount, then it is possible for a force account that affects final contract amount to incur costs for the public liability insurance coverage. If the contractor purchases additional public liability and property damage insurance policies specifically for the force account work, they can be reimbursed their actual costs for the additional insurance policies under subsection 109.05.D.4. Only costs actually incurred by the contractor related to the force account work will be reimbursed after receiving proof of payment. The required documentation for proof of payment is:
- A policy written specifically for the force account work.
- A statement showing adjustments to a policy directly attributed to the force account work along with proof of payment of the amount.
Payments for PLPD insurance costs directly attributable to force account work and not covered by the existing required broad PLPD policies are rare in force account billing. Additionally, any such calculation as indicated in the second bullet point above must also include all deductions for all duplicate coverages. (E.g. trucks and their drivers are already covered under the existing vehicle insurance policy which is reimbursed under the equipment section of subsection 109.05.D.6). Any equipment with a license plate (e.g. on road vehicle) would likely fall under this requirement and have to be segregated out of any insurance calculations.
- State Unemployment Insurance:
Payments made for State Unemployment Insurance on behalf of workers performing work under force account are eligible for reimbursement. A contributing employer files a tax report with the Unemployment Insurance Agency at the end of each calendar quarter, and pays a state unemployment tax on the first $9,000.00 of wages paid to each worker performing covered services in a calendar year. The amount of the tax is determined by the employer’s state unemployment tax rate. The rate is discussed in much more detail in the handbook entitled "Employers’ Guide to Unemployment Insurance Taxes." For employees with less than $9,000 of earnings for the tax year to date which the force account work has taken place, an amount equal to the percentage paid of their wages to Unemployment Compensation, will be reimbursed at cost. The required documentation for payment is:
- The Michigan Unemployment Insurance Form UIA 1028, Employer's Quarterly Wage/Tax Report.
- Certified payrolls indicating employee total year to date earnings of less than $9,000 during the time of the force account work, or,
- Calculations from contractor payroll department certifying the total number of hours each eligible worker performed work on the force account before they earned the year to date maximum and were no longer eligible for reimbursement.
- Proof of payment is not required as this is a state mandated employment payment and is regulated through those departments.
- Federal Unemployment Insurance:
- The Federal Unemployment Tax Act (FUTA) taxes are calculated by multiplying 6.0% times the employer's taxable wages. The taxable wage base is the first $7,000 paid in wages to each employee during a calendar year. Employers who pay their state unemployment taxes on a timely basis receive an offset credit of 5.4% regardless of the rate of tax paid to the state. The FUTA tax rate for employers in states subject to a FUTA credit reduction (Michigan) is generally 0.6% (6.0% - 5.4%), for a maximum FUTA tax of $42.00 per employee, per year (.006 X $7, 000 = $42.00). The net federal tax, after full credit, is 0.6%, multiplied against the first $7,000 of wages of each employee covered under the federal law.
- Documentation required to support federal unemployment tax costs on force account are identical to those stated for state unemployment above but applied only to the first $7,000 the worker earns which is a maximum payment of $42/year per worker or less.
- Contractor must provide year to date earnings for each employee to determine eligibility for FUTA insurance reimbursement on force account work.
Federal Social Security and Medicare
Federal Social Security and Medicare taxes are paid by both the employee and the employer. The employee portions are not eligible for reimbursement under force account, but the employer portions are.
- For 2016, the social security tax rate is 6.2% (amount withheld) each for the employer and employee (12.4% total). The 2016 social security wage base limit is $118,500, see link for annual update to social security tax rate and wage limit: (http://www.ssa.gov/oact/cola/cbb.html)
- The tax rate for Medicare is 1.45% each for the employee and employer (2.9% total). There is no wage base limit for Medicare tax; all covered wages are subject to Medicare tax.
Until the wage limit cap has been met by each employee, a total of 7.65% (6.2%+1.45%) of wages paid by the employer is eligible for reimbursement under force account procedures. The required documentation for proof of payment is:
- Certified payrolls indicating employee total year to date earnings of less than $118,500 (2016 rate) during the time of the force account work, or,
- Calculations from contractor payroll department certifying the total number of hours each eligible worker performed work on the force account before they earned the year to date maximum and were no longer eligible for reimbursement.
For any of the above items that are lacking the supporting documentation, there will be no reimbursement of costs. For items that have the required supporting documentation they will be reimbursed for the actual cost plus an additional 11% markup to those individual costs.
Materials are items that are permanently incorporated into the project. This does not include temporary items that are part of the contractor’s means and methods to complete the work.
For materials used and accepted by the engineer the contractor will receive the cost of materials delivered including tax and transportation charges plus 15 percent overhead. Materials such as tarpaulins and mats, etc. that are not incorporated into the finished work and retained by the contractor are considered to be overhead.
Contractors are reimbursed actual costs of material delivered to site, including freight. An invoice or a bill for materials is not by itself sufficient documentation to prove payment was made. A copy of a paid invoice from the supplier with a check number/electronic transfer, or copy of the cancelled check proving payment must be attached to the force account statement. Credit for contractor’s discounts must be included on the invoice, penalties for late payment will not be considered.
Any materials incorporated permanently on the project needs a Materials Source List (MSL), material certification/test report, and Buy America certification requirements for steel.
Materials from a contractor’s stock will meet the requirements per the Material Quality Assurance Procedures (MQAP) manual. Also contractors need to submit an affidavit certifying the following:
- The materials were taken from stock.
- The quantity was used.
- The cost including transportation represent the contractor’s actual cost.
Sales tax for purchase of materials will be allowed when the contractor provides documentation that they have paid it.
When the work plan specifies quantities of an item and those items have been delivered to the jobsite, the costs for returning any unused items can be reimbursed at actual costs. These costs may include transport, handling and restocking fees however, the 15% overhead mark-up does not apply. Restocking fees must be disclosed on the original invoice terms and conditions.
For force accounts where the work plan specifies customization of an item, non-standard items, or other items that are unique to the force account work the department will reimburse the contractor for actual costs. This may include:
- MDOT retention of the item with associated shipping and handling costs.
- Restock of the item with associated shipping and handling costs.
- Scrap of the item and associated shipping and handling costs.
If the contractor decides to retain the item, the department will not reimburse the cost of the item.
Determination of the rental and operating rates will follow subsection 109.05.D.6.a.i of the 2012 Standard Specifications for Construction. The equipment costs need to be determined for the time period which the force account work was performed. The EquipmentWatch Blue Book must be used to determine the reimbursement rates for equipment, these rates can be located on the EquipmentWatch website. Department employees can access the EquipmentWatch Blue Book information via a link located on the Construction Field Services SharePoint page. Non MDOT personnel should contact their respective TSC’s to obtain copies of EquipmentWatch pages.
Determination of the rental and operating rates, for a similar piece of equipment, will follow subsection 109.05.D.6.a.ii of the 2012 Standard Specifications for Construction. Rates must be agreed upon and documented before the equipment is used. Allowable rates for miscellaneous contractor owned equipment typically not listed in the Blue Book are available on the link below:
Allowable rates for contractor owned equipment
Contractors have the option of using the above published allowable rates for contractor owned equipment not listed in Blue Book or providing standard purchasing documentation and depreciation tables to justify higher rates. If standard rates are selected, no further documentation will be required.
Custom Made Equipment The custom made equipment cost needs to be appraised by a certified public accountant for the calendar year which the force account work was performed. The monthly rate must be reasonable but not more than 5% of the annual appraised invoice cost. The price must be agreed to in the work plan before the equipment is used.
No payment will be allowed for small hand and power tools that are not listed in the Blue Book or are listed at a rate of less than $1.00 per hour.
When small tools or equipment are used on a project and where it may be difficult or unreasonable to establish the age, the engineer and contractor will agree on an age to apply to all small tools or equipment (e.g., air hose, pump hose, cut-off saws, jack-hammer, etc.).
Consumable supplies (welding rod, welding gas, gasoline, diesel, etc.) will be considered incidental and will not be reimbursed separately.
Travel time to the location of the force account work will be included when the equipment is moved under its own power. When equipment is moved from one site to another by means other than its own power, the actual operating time during periods of loading and unloading equipment will be paid for at the established base hourly rate and transportation costs will be allowed.
Transportation charges for each piece of equipment to and from the work site will be paid, provided, the
- Equipment is obtained from the nearest available source;
- Return charges do not exceed the delivery charges; and
- Charges are restricted to those units of equipment not already available and not on or near the project.
If the department suspends force account operations, the contractor may be subject to reimbursement under the provisions for payment for idled equipment and labor per subsection 109.05.E.
If the contractor is required to rent a specific type of equipment, the contractor must inform the engineer of the need to rent the equipment and provide a documented estimate from the rental agency for that equipment before using it on the work site. The contractor will be paid the actual rental cost plus the Blue Book operating rate for the time that the equipment is used to accomplish the work, plus the cost of moving the equipment onto and away from the job. The contractor must provide a copy of paid invoices for all rental expenses incurred.
The rental rate is paid for only the time used by the hour, not weekly or monthly. The estimated operating cost per hour includes fuel, energy, oil, grease and parts, and other operating expendables such as labor assigned to service equipment or vehicles (this includes operator grease time) unless the estimated operating cost specifically notes otherwise.
For contractor-owned equipment, the standby rate will be one-half the rental rate established in subsection 109.05.D.6.c (No operating costs allowed). The standby rate will only be allowed if the engineer specifically requires the equipment to remain on the site for later use on the force account work.
The engineer will provide documented notice when the equipment is no longer needed to complete the force account work and will not be considered for payment, except for transportation costs.
Payments for standby time will not be made on any day the equipment operates for eight or more hours. For equipment accumulating less than eight hours operating time, standby payment will be limited to the difference of 8 hours less the operating time for that day. Saturdays and Sundays are not to be included unless provided for in the contract.
For administration costs in connection with subcontract work or hiring services by others to perform specialized work that the contractor is not qualified to do, the contractor will receive an amount equal to five percent of the total cost of the work. No additional payment for multiple tier subcontractors are allowed without prior approval by the engineer per subsection 109.05.D.7 of the 2012 Standard Specifications for Construction. No additional markup is to be paid to the subcontractor performing the work or overseeing the work of a multiple tier subcontractor.
Subcontractor/specialty service company should correspond to the name of the company listed in the work plan. For payment of invoice the contractor is required to submit documentation showing the proof of payment to the sub/specialty services.
Projects containing the Special Provision for Force Account Business Taxes 12SP-109B-01 the contractor will not be eligible for business tax reimbursement.
On projects let prior to the approval of 12SP-109B-01 contractors may receive an amount equal to 3.5% of the total force account to compensate for business tax.
No additional allowance will be made for general superintendence or other cost for which no specific cost is provided in the specification per subsection 109.05 D.9.
The engineer is responsible for ensuring the work is performed per the work order and work plan. The engineer must complete form 1101A - Force Account Daily Field Record Sheet. The superintendent or foreman for the contractor and the engineer are both to sign form 1101A. This form is to be completed at the end of each day's work or not more than 48 hours’ time period after completion of that days force account work. The signatures indicate that agreement was reached at the end of each day between the engineer and the contractor regarding the material, equipment, and time reported. The engineer or authorized representative must keep an accurate daily record of the time and materials cost to the contractor. In the event the contractor declines to sign form 1101A, the department records will govern. Any item not shown on form 1101A will not be eligible for payment per subsection 109.05.D.10.
The contractor is required to submit form 1101 spreadsheet weekly.
At the end of the force account work the engineer must review all the force account documents before final payment is made and report it on an Inspector Daily Report (IDR).
Report should contain key information such as listed below:
- Labor hours matching certified payrolls, IDR’s, 1101A – Force Account- Daily Field Record, and the 1101 Force Account Statement spreadsheet.
- Materials – Check material certifications.
- Equipment –attach printouts from blue book (equipment watch).
- Restocking fee.
Pay Item Units
Force account is a cost reimbursement procedure, therefore, pay units other than dollar or lump sum should not be used. All force accounts must use one of the two pay item codes listed below.
|Item Code||Item Description||Unit|
|1090002||Force Account #1||Dlr|
|1090003||Negotiated Force Account||Lump Sum|
To be used for all time and material/force account situations. Partial payments can be made using this pay item based on Engineers acceptance of the work and approval of supporting documentation (see Contractor Payment Section). The negotiated force account pay item code must be used when work which commenced under the force account method has since been negotiated by the engineer and contractor to be a lump sum item of work.