Cost Plus Fixed Fee (CPFF) vs Time and Materials — When Each Contract Type Wins for Small Contractors

A Cost Plus Fixed Fee (CPFF) contract is a cost-reimbursement federal contract type that pays the contractor for actual allowable, allocable, and reasonable costs plus a fixed dollar fee for profit, while a Time and Materials (T&M) contract pays a fixed loaded hourly rate per labor category multiplied by hours worked, with materials reimbursed at cost. FieldLedger handles both contract types in the same workspace by tracking direct hours and indirect cost pools per FAR 31.2, producing provisional billing rate letters for CPFF and rate-validation invoices for T&M from the same signed timekeeping data.

After firm-fixed-price (FFP), the two contract types small federal contractors see most often are Cost Plus Fixed Fee (CPFF) and Time and Materials (T&M). Both reimburse actual costs differently. Both carry different DCAA scrutiny. Both demand specific accounting capabilities. This is the practical breakdown.

The 30-second version

Dimension	CPFF	T&M
Revenue model	Allowable costs + fixed dollar fee	Loaded hourly rate × hours + materials at cost
Risk to contractor	Low (cost reimbursable)	Medium (rate is fixed, hours vary)
Risk to government	Higher (cost overruns up to ceiling)	Lower (cap on rates)
DCAA accounting requirement	DCAA-compliant accounting system mandatory	DCAA-compliant accounting required for billing
Indirect rate billing	Provisional rates, settled annually	Built into loaded rate
Common uses	R&D, system engineering, professional services	Skilled labor for defined tasks

CPFF protects you from cost overruns but requires the most rigorous accounting. T&M is operationally simpler but caps your margin and requires hour-by-hour discipline.

CPFF — Cost Plus Fixed Fee

CPFF reimburses your actual allowable costs plus a fixed dollar fee for profit. The fee doesn't change if costs change (within the contract ceiling). Your incentive is to manage costs efficiently — but cost overruns up to the ceiling are reimbursable.

Mechanics:

• Contract specifies an estimated cost (e.g., $1.5M) and fixed fee (e.g., $150K = 10%)
• You incur direct labor, materials, and ODCs
• You apply provisional indirect rates (fringe, overhead, G&A) to direct costs
• You bill monthly: actual direct costs + applied indirects + pro-rata share of fixed fee
• At year-end, you submit incurred-cost proposal; rates settle to actuals
• Contract caps total reimbursable cost at the ceiling (e.g., $1.5M)

What you need to bill CPFF:

• DCAA-compliant accounting system (audit trail, project cost segregation, indirect rate calculation)
• Provisional indirect rates approved or accepted by DCAA
• Monthly accumulation of direct costs by project
• Year-end incurred-cost proposal capability
• ICE-format reports for DCAA audit

Where CPFF goes wrong:

• Cost overruns above the ceiling are unreimbursable. You eat them.
• Disallowed costs reduce your settlement at year-end. Unallowables in the project cost = direct hit to fee.
• Indirect rate variances (provisional vs actual) create reconciliation work.
• DCAA audits CPFF contracts more aggressively than other types.

T&M — Time and Materials

T&M pays a fixed loaded labor rate per hour worked plus materials at cost (sometimes with a small handling fee). The labor rate is built to cover direct labor + fringe + overhead + G&A + profit.

Mechanics:

• Contract specifies labor categories (e.g., Senior Engineer at $185/hr loaded) and quantity (e.g., 8,000 hours over 18 months)
• You bill hours actually worked × the loaded rate
• Materials and ODCs bill at actual cost (sometimes with a small markup, e.g., 5%)
• The contract caps total dollars (rate × hours + materials)
• No year-end indirect rate settlement

What you need to bill T&M:

• DCAA-compliant timekeeping (every hour logged with project + labor category + user attribution)
• Documented labor-category mapping (which employees qualify for which rate)
• Materials and ODC documentation
• Backup invoices and receipts for material costs

Where T&M goes wrong:

• Hours worked above estimate are billable up to the ceiling — but margin compresses if your loaded rate didn't cover actual costs.
• Labor-category misuse (billing a junior engineer at the senior rate) is a False Claims Act exposure.
• Overtime treatment varies by contract; uncompensated overtime affects your accounting.
• Material markups are typically small (5% or less); not a profit center.

The DCAA accounting standard for both

Both CPFF and T&M require a DCAA-compliant accounting system per FAR 31. Specifically, you need:

1. Project cost segregation. Costs accumulated by contract, not commingled.
2. Direct vs indirect cost identification. Clear policy on what's direct, what's indirect.
3. Allowable vs unallowable cost segregation. Per FAR 31.205.
4. Timekeeping with audit trail. Every entry attributable, immutable, retained.
5. Indirect rate calculation capability. For CPFF, billing requires provisional rates.
6. ICE Model Schedule production. For year-end DCAA submissions.

This is what FieldLedger does. We don't run the GL — QuickBooks Online handles that. We handle the project cost segregation, indirect rate calculation, timekeeping, and federal invoicing layer.

Which to bid for

Bid CPFF when:

• The scope is uncertain (R&D, system engineering, exploratory work)
• Cost growth risk is high
• You can absorb the year-end indirect rate settlement complexity
• Your accounting system handles provisional rates and incurred-cost submissions

Bid T&M when:

• The scope is well-defined but level-of-effort is uncertain
• The customer wants flexibility to add or reduce hours
• Your direct labor model is well-understood
• You want simpler monthly billing

Bid FFP when:

• Both scope AND level-of-effort are well-defined
• You're confident in your cost estimate
• You can absorb cost overruns from estimation errors

The contracting officer chooses the contract type, not you. But your bid response can suggest a different type if the proposed type doesn't match the work.

Hybrid contracts (CPFF + T&M)

Many real contracts combine types. A common pattern: CPFF for the technical management portion + T&M for the development hours + FFP for specific deliverables.

This is messy operationally. Each line item has its own billing rules. You need to:

• Track costs separately by line item
• Apply the right billing methodology to each
• Bill on a single monthly invoice but with line-item detail
• Manage three different reconciliation patterns at year-end

A capable accounting system handles this; manual processes break under it.

CPFF risk allocation

Federal CPFF contracts typically allocate risk this way:

Risk	Who carries it
Cost growth within ceiling	Government (cost reimbursable)
Cost growth above ceiling	Contractor (unreimbursable)
Disallowed costs	Contractor (reduces settlement)
Indirect rate variance	Shared (true-up at year-end)
Schedule slip	Shared (no fee adjustment but costs continue)

The contractor's main exposure is exceeding the ceiling and accumulating unallowable costs. Both are accounting-discipline issues.

T&M risk allocation

Risk	Who carries it
Hours growth within ceiling	Government (paid for hours billed)
Hours growth above ceiling	Contractor (unreimbursable)
Loaded rate inadequacy	Contractor (margin compression)
Material price changes	Government (actual cost reimbursable)
Schedule slip	Shared

The contractor's main exposure is loaded-rate inadequacy. If your rate doesn't cover actual fully-loaded labor costs, every hour billed under-recovers.

Common SMB mistakes

1. Bidding T&M with under-loaded rates. Loaded rate must cover direct labor + fringe (~30% of base) + overhead (~30% of direct labor + fringe) + G&A (~10% of total) + profit (~7-15%). If your rate is base × 1.3 × 1.3 × 1.1, that's 1.86× — barely covering costs. Industry standard is ~2.2× to 2.5× base salary as loaded rate.

2. CPFF without provisional rate approval. Billing CPFF requires DCAA-accepted or contractor-proposed provisional rates. If you bill without them, expect billing rejections and slow payment.

3. Mixing project costs across contracts. A single timesheet entry to "general support" allocated across three projects = a CPFF audit finding. Be specific.

4. Failing to segregate unallowable costs in real-time. If your bookkeeper categorizes the holiday party as "team building" without flagging it as unallowable, that cost flows into your indirect pools and your billing — until DCAA catches it years later.

5. Misclassifying labor categories on T&M. Billing a junior engineer's hours at the senior rate (because they're doing senior work) is a False Claims Act exposure even if the work quality justifies it. Pre-clarify with the contracting officer or hold those hours back.

What FieldLedger handles

For both CPFF and T&M, FieldLedger handles:

• DCAA-compliant timekeeping (every entry logged, attributable, immutable)
• Project cost segregation
• Direct vs indirect cost mapping
• Indirect rate calculation (provisional and actual)
• Federal invoicing in the format the agency expects (ICE Model Schedule, DD-250-style invoices, T&M hourly logs)
• Unallowable cost segregation
• Year-end ICE Model Schedules (H/I/K/L)
• Audit trail satisfying NIST 800-171 family 3.3 for the accounting subsystem

What FieldLedger doesn't handle:

• The GL itself (use QuickBooks Online)
• AP / AR (use QBO)
• Payroll (use Gusto / ADP)
• Multi-subsidiary consolidation (out of scope at our target customer size)
• CAS-specific Disclosure Statement support (we serve sub-CAS contractors)

What to do this quarter

1. Audit your contract mix. Count by type — FFP / CPFF / T&M / hybrid. Make sure your accounting handles each.

2. Validate provisional rates with DCAA. If you're bidding CPFF and don't have a current provisional rate package, get one approved before the next major bid.

3. Recalculate your T&M loaded rates against actuals. If your rates are based on 12-month-old assumptions, they may be under-loaded.

4. Implement labor-category enforcement. Don't allow timesheet entries against incompatible categories.

5. Run a test indirect rate calculation. Make sure your accounting system produces the rates correctly. If it doesn't, fix that before year-end.

Related reading

• Cost Accounting Standards (CAS) explained
• Contractor billing software comparison
• DCAA-compliant timekeeping software under $200/month
• Deltek Costpoint alternative — FieldLedger comparison