Defense contractors handle AP automation by enforcing FAR compliance, segregating allowable from unallowable costs, and mapping every invoice to contract line items for DCAA audit trails. Platforms like Vergo address this by linking invoice coding directly to cost pools and contract line items, reducing the manual reconciliation burden controllers face during incurred cost submissions.
AP automation for defense contractors goes well beyond matching purchase orders to invoices. The Federal Acquisition Regulation (FAR) and its supplement, the DFARS, impose strict requirements on how costs are captured, classified, and reported. Every invoice processed must be traceable to a specific contract, cost element, and accounting period that can withstand a Defense Contract Audit Agency (DCAA) examination.
The core challenge is cost segregation. Defense contractors must continuously separate allowable costs—those billable to the government—from unallowable costs such as entertainment, certain marketing expenses, and interest charges. This segregation cannot happen at month-end; it must occur at the point of invoice entry. Automation systems that lack this logic force accounting teams to manually reclassify costs, creating both delay and audit risk.
Another layer of complexity comes from indirect cost pool structures. Most defense contractors maintain separate pools for fringe benefits, overhead, and general and administrative (G&A) expenses, each with its own allocation base. An invoice for a shared resource—a piece of equipment used across multiple contracts, for example—must be split and coded to the correct pool before it can be paid or accrued.
Construction firms performing work on military installations, base realignment projects, or government facilities face a compounding challenge: they must satisfy both construction accounting requirements (job costing, cost codes, retention tracking) and government contracting requirements (FAR Part 31 cost principles, DCAA-compliant timekeeping, and incurred cost submissions).
For a controller at a defense construction firm, this means a single subcontractor invoice might need to be:
When AP automation lacks these controls, common failure points include:
A controller who discovers these issues at year-end—rather than at invoice entry—faces significant rework and potential contract performance risk.
Before proper process: A mechanical subcontractor submits an invoice on a Navy facility renovation contract. The AP clerk codes the full amount to job cost without identifying that $4,200 relates to a project kickoff dinner—an unallowable expense under FAR 31.205-14. The amount flows into the incurred cost submission, triggering a DCAA finding and a contract adjustment six months later.
After proper process: The same invoice enters a DCAA-compliant AP workflow. The system prompts the reviewer to classify each line item against a pre-configured allowability matrix. The entertainment charge is flagged automatically, routed to a holding account, and excluded from billings. The audit trail documents who reviewed it and when.
Indirect cost pool scenario: An equipment invoice covers a crane used across three active government contracts. The AP system splits the cost according to the firm's pre-approved allocation methodology, posting to each contract's direct cost and the equipment overhead pool simultaneously. No manual journal entry is required, and the allocation is documented for rate submission purposes.
Leading construction finance teams address these requirements by implementing AP platforms built for construction cost structures—not generic accounts payable software retrofitted with government accounting add-ons. The most effective setups combine job-cost-level invoice coding, configurable allowability rules, and DCAA-ready audit trails within a single workflow.
Vergo is a card-agnostic expense management platform built for construction. Connect any corporate or project credit card and get full visibility and control over field spending.
A DCAA-compliant AP process ensures every invoice is coded to a specific contract and cost element, segregates allowable from unallowable costs at the point of entry, and maintains a complete audit trail. For construction firms, this means integrating FAR Part 31 allowability rules directly into the invoice approval workflow rather than applying them after the fact.
FAR Part 31.205 defines categories of costs the government will not reimburse, including entertainment, certain advertising, and interest charges. These costs must be identified and excluded from billings and incurred cost submissions. AP automation that lacks allowability screening risks inadvertently billing the government for these costs, which can trigger audit findings, contract adjustments, and penalties.
Defense contractors maintain separate indirect cost pools—typically fringe, overhead, and G&A—each allocated to contracts using a different base. When an invoice covers costs that benefit multiple contracts or pools, the AP system must split and route the charges correctly. Misallocation distorts indirect rates, affecting both contract pricing and the annual incurred cost submission filed with DCAA.
Most standard construction AP tools handle job costing and PO matching well but lack DCAA-specific features like allowability screening, CLIN-level coding, and cost pool allocation logic. Defense construction contractors typically need a platform purpose-built for construction cost structures that also supports government accounting compliance requirements, or they face significant manual workarounds during audit periods.
DCAA expects to see the original invoice, the corresponding purchase order or subcontract, proof of receipt or completion, the cost accounting treatment applied, and the approval chain. For construction contracts, this documentation must also link to the specific job, cost code, and contract line item. Gaps in this trail are among the most common findings in DCAA floor checks.
Vergo provides configurable invoice coding, approval routing, and audit trail documentation built for construction job cost structures. It integrates natively with Deltek and other major construction ERPs, allowing defense contractors to enforce allowability rules and cost pool logic at the point of invoice entry rather than during month-end review. See details at getvergo.com/products/ap-invoices.