Overview
A global oil and gas technology and services company hired a contracted labor supplier. The supplier provided specialized instrumentation, electrical, and mechanical technicians across many field sites and shifts. These crews supported upstream operations including equipment installation, commissioning, reliability work, and 24/7 maintenance.
Over time, the company’s accounts payable team noticed invoice inconsistencies that were hard to explain. Overtime charges spiked unevenly, shift pay was applied inconsistently, and manual billing adjustments increased. With contracted labor representing a meaningful share of maintenance and turnaround spend, the company launched a Contract Compliance Recovery Audit to determine whether billings aligned with what the contract actually required.
Challenge
Contracted labor billing in field-intensive industries is inherently complex. Pay rates vary by job type, shift, location, and overtime rules. These rules come from detailed contract terms and must be applied the same way across hundreds of weekly timesheets and invoices.
During a period of significant workforce disruption and urgent work orders, billing processes became increasingly manual. Time entry became inconsistent across locations, and the supplier and AP team began to interpret contract terms differently. This led to errors that built up over time and were hard to catch in normal invoice reviews, but added up to a large impact.
Without a dedicated compliance review, these billing inaccuracies would have continued undetected, representing ongoing financial leakage in a high-spend category.
Solution
apexanalytix conducted a Contract Compliance Recovery Audit, defined as auditing a specific contract’s financial terms against underlying transactions to identify non-compliance resulting in overpayment. The audit covered a three-year period and examined labor billings across all in-scope work sites and job roles using the following approach:
- Stakeholder Alignment: Confirmed audit scope and schedule with contract owners, AP, and operations teams to ensure shared understanding of contract intent and audit boundaries.
- Transactional Data Collection: Gathered complete billing history from both customer and supplier systems, ensuring a full population of invoices and timekeeping records was available for testing.
- Contract-to-Invoice Testing: Tested labor billings against contract terms across the full population where possible, applying statistically valid sampling with extrapolation where needed.
- Exception Memos: Used structured Exception Memos to quickly validate facts with both parties during fieldwork, reducing back-and-forth and accelerating resolution.
- Collaborative Settlement: Negotiated findings with a “collaborative first” posture, reserving formal settlement meetings only for unresolved exceptions to maintain the supplier relationship.
Results
The audit identified $2 million in overbillings spanning multiple work sites, job roles, and billing categories.
The largest driver of recovery was billed taxes incurred. The supplier invoiced withholding and payroll taxes at amounts that exceeded what was actually incurred, resulting in tax charges that significantly exceeded real employer liability. This single finding accounted for the majority of total dollars recovered.
Additional overbillings were identified across several other areas:
- Pay class vs. bill class mismapping. Higher-rate labor classifications were billed for work performed at lower-rate classifications, resulting in overbilling on a per-hour basis across a significant volume of transactions.
- Excessive overtime and shift premium application. Overtime and shift differential premiums were applied outside the rules defined in the contract, inflating invoice amounts beyond what was contractually permitted.
- Hours billed exceeding hours paid. Invoiced hours consistently exceeded hours reflected in the supplier’s timekeeping records, creating direct overbilling against the labor actually delivered and compensated.
Conclusion
Contracted labor is one of the most difficult spend categories to control. Billing errors rarely announce themselves. They accumulate quietly across timesheets, job classifications, and tax calculations until a structured audit brings them into view.
The Contract Compliance Recovery Audit recovered $2 million in overbillings, with unemployment tax overcalculation emerging as the single largest source of exposure. With root causes now identified and documented, the company has a clear path forward to close control gaps and better protect margins on contracted labor spend.
