The Change-Order Margin Model: Price the Delay, Not Just the Extra Work

A customer asks for $12,000 of additional work. The estimator prices $12,000 of labor and material, adds markup, and believes the change is profitable. Then the crew waits, the schedule moves two weeks, supervision stays on site, equipment remains rented, and billing does not happen for 45 days.

The extra work may still be worth doing. The original price did not capture the change.

A change-order margin model starts with added and deleted scope, then prices the effect on sequence, time, overhead, productivity, cash, and risk. The approved change should protect both the incremental work and the base contract from cost the change causes.

Read the contract before using the model

The agreement controls notice, authorization, pricing, time extensions, markup, documentation, claims, and the obligation to proceed. Public-contract clauses can have specific requirements that do not apply to a private job, and state law may affect enforceability and payment.

The Federal Acquisition Regulation, for example, addresses documentation, equitable adjustments, segregable cost, and delivery-schedule changes for covered federal contracts. That is useful evidence that price and time are separate change components. It is not a template for every customer agreement.

Project leadership and counsel should confirm the actual process. Finance should make sure the operational model supplies timely, supportable cost and schedule evidence.

Separate scope cost from change impact

Build the price in layers.

Layer 1: added and deleted direct work

• Field labor hours and approved wage rates.
• Payroll burden and benefits.
• Materials, freight, tax, and waste.
• Subcontractors.
• Equipment used for the changed work.
• Permits, testing, design, and engineering.
• Credit for scope deleted or avoided.

Layer 2: disruption and resequencing

• Stop-and-start productivity loss.
• Crew reassignment and remobilization.
• Out-of-sequence work.
• Repeated setup, protection, or access.
• Rework to preserve completed work.
• Expediting and premium freight.
• Overtime or shift premium caused by the change.

Layer 3: schedule and time-related cost

• Site supervision and project management.
• Temporary facilities and utilities.
• Equipment, storage, security, and insurance.
• Travel and lodging.
• Bond or permit extension where applicable.
• Head-office support that genuinely extends with the job.

Layer 4: financing and risk

• Cash paid before the change is billed and collected.
• Retainage or delayed approval.
• Uncertain quantity or site condition.
• Supplier and subcontractor price validity.
• Warranty and closeout exposure.
• Approved overhead and profit under the contract.

Do not call every layer “overhead.” Naming the cause makes the proposal easier to support and the forecast easier to control.

Use an incremental change-order formula

Change-order contribution
= Approved change revenue
  – Added direct work cost
  + Cost avoided from deleted work
  – Disruption and resequencing cost
  – Time-related extension cost
  – Incremental financing and risk cost

Change-order margin
= Change-order contribution ÷ Approved change revenue

Keep the contract's allowed markup calculation separate from the internal profitability calculation. The agreement may permit a percentage on certain cost categories and exclude others. Internal cost does not disappear when it is not recoverable.

Work through a two-week delay

Assume a customer-directed design change adds equipment, labor, and two weeks to a field-service installation. This example is hypothetical.

Cost element	Amount
Added field labor	$7,200
Payroll burden and benefits	$1,800
Materials and freight	$8,000
Subcontractor change	$3,400
Added field supervision	$2,400
Remobilization and repeated setup	$1,800
Two weeks of site and equipment cost	$5,600
Resequencing and productivity effect	$3,100
Financing, warranty, and specific risk allowance	$1,200
Total modeled incremental cost	$34,500

If the contractor prices only the first four rows, it sees $20,400 of obvious work. At a 20% markup on that cost, it proposes $24,480.

Proposed revenue based on obvious work  $24,480
– Full modeled incremental cost          34,500
= Modeled change-order loss            ($10,020)

To earn a 15% internal contribution margin on the full $34,500 cost:

Required price
= $34,500 ÷ (1 – 15%)
= approximately $40,588

The contract may not permit every dollar or pricing method. The model still exposes the economic gap before management authorizes work or absorbs the consequence silently.

Want to test this against your own numbers? Book a free 20-minute Profit & Tax Leak Check to pinpoint the first profit, tax, cash-flow, or financial-structure issue worth fixing.

Price time with a schedule analysis

Not every added task extends the completion date. It may have float, replace other work, or run concurrently. Conversely, a small task on the controlling sequence can move the whole job.

For each material change, record:

• Required activity and predecessor.
• Baseline start and finish.
• Changed start and finish.
• Available float under the approved schedule.
• Crew and equipment impact.
• Critical or controlling path effect.
• Mitigation or acceleration option.
• Customer, contractor, third-party, and concurrent causes.

Use the scheduling method required by the contract and reviewed by qualified project leadership. Finance should not invent a delay entitlement. It should calculate what each supported time scenario costs and what it does to cash.

Distinguish extension from acceleration

A customer may want the extra work without moving the completion date. That is an acceleration decision.

Model alternatives:

Option	Likely cost pattern
Extend completion	Time-related site cost, supervision, equipment, later cash
Add crew	Mobilization, supervision, congestion, availability premium
Add overtime or second shift	Wage premium, fatigue, coordination, lighting/access, quality risk
Resequence	Productivity loss, temporary work, repeated setup, trade interference
Reduce other scope	Credits, dependency changes, warranty or acceptance effects

Do not assume overtime restores one hour of delay for every added hour. Measure actual productive output, handoffs, access, and rework.

Protect the base contract margin

The change-order P&L is not enough. A change can damage unchanged work.

Create a bridge:

Prior forecast final project contribution
+ Approved change contribution
– Unrecovered change cost
– Base-work disruption caused by the change
– Delay and acceleration not included in the change
± Other estimate changes
= Current forecast final project contribution

If the change earns $8,000 but creates $14,000 of unrecovered disruption in the base job, the project did not improve by $8,000.

The percentage-of-completion framework explains how approved modifications, transaction price, cost estimates, and WIP may affect financial reporting. This margin model controls the operating economics; the qualified accountant controls revenue recognition.

Manage pending work separately

Use statuses that match the contract:

• Identified potential change.
• Notice submitted.
• Scope defined.
• Price and time proposal submitted.
• Authorized to proceed, price pending.
• Fully approved price and time.
• Disputed.
• Rejected.
• Closed and collected.

Do not include a hoped-for amount in booked change revenue. Do not hide cost until approval. Record cost to the project and separately show the recovery status so leadership can see the cash exposure.

For every unpriced change:

Cash exposure to date
= Paid labor, materials, subcontractors,
  equipment, and time-related cost incurred
  – Cash collected specifically for the change

Set an approval limit and stop/escalation rule that complies with the contract. Continuing indefinitely on verbal direction converts a commercial issue into a financing decision the contractor may not have approved.

Include deleted scope and credits fairly

A deletion does not always remove the original estimated cost dollar for dollar. Some materials may be committed, labor may be redeployed inefficiently, or overhead may remain.

Calculate:

Avoidable cost credit
= Original cost that will no longer be incurred
  – Cancellation, restocking, and wind-down cost

Follow the agreement for markup and credit treatment. Keep sunk cost, avoidable cost, and remaining fixed cost separate.

Close the loop in the project forecast

Every week, reconcile:

1. Change log to written notices and authorization.
2. Estimate to segregated actual cost.
3. Schedule effect to the approved update.
4. Approved amount to billing.
5. Billing to receivables and cash.
6. Change contribution to forecast final project margin.
7. Pending exposure to the cash forecast and approval limit.

The job-costing framework provides the cost detail. The unbilled-revenue process can track valid earned amounts awaiting billing without treating every unapproved claim as an asset.

Use a go/no-go change gate

Before committing material work, require:

• Contract notice and authorization path confirmed.
• Added and deleted scope defined.
• Direct, disruption, schedule, financing, and risk cost estimated.
• Price and time adjustment modeled separately.
• Base-contract margin bridge updated.
• Cash exposure and billing event forecast.
• Executive approval for unrecovered exposure.
• Named owner and next document date.

The useful sentence is not “the customer approved $24,480.” It is: “The change costs $34,500 after the supported two-week effect; the proposed price loses $10,020; we will not mobilize beyond the written authorization limit until price, time, or an approved commercial concession resolves the gap.”

Sources

• Acquisition.gov: FAR 43.204—Change Order Administration
• Acquisition.gov: GSAR 552.243-71—Equitable Adjustments
• Acquisition.gov: DFARS 252.217-7003—Changes
• Financial Accounting Standards Board: Revenue Recognition Implementation Questions and Answers

Fractional CFO support can connect estimating, schedule, change logs, WIP, billing, and cash into one margin control. The Profit & Tax Leak Check can identify whether unpriced delay, weak notice, hidden disruption, underbilling, or slow collection is draining project profit.