How Barton Associates reduced invoice disputes by 52% with Nace

Barton Associates brought contract verification into its billing workflow with Nace, connecting contract terms, timesheets, expenses, and invoice calculations in one auditable process.

“With Nace, we were able to review 10,000 invoices end to end, strengthening our billing workflow and surfacing meaningful revenue leakage that would have been hard to catch manually.”

April Hensen, CEO, Barton Associates

When every assignment has different billing rules

Barton Associates is a locum tenens staffing agency serving healthcare facilities across all 50 states and U.S. territories. Its network spans more than 120 practice areas.

Every assignment comes with unique billing terms. Rates, overtime rules, holiday pay, reimbursable expenses, and special provisions vary by contract. This creates multiple points for pre-billing errors:

• Incorrect base or overtime rates
• Unbilled or misapplied holiday pay rules
• Reimbursable expenses charged outside contract terms
• Uncaptured shift hour variances or duplicate charges
• Contract-specific provisions missed during manual review

Across high invoice volumes, catching these discrepancies manually is nearly impossible, resulting in delayed payments and revenue leakage.

Turning contracts into automated, auditable billing logic

Contract + timesheet + expenses → automated verification → evidence → invoice.

Barton moved contract verification into the billing process itself.

Nace works on top of existing ATS, VMS, and ERP systems, adding verification and reasoning without requiring teams to replace their core systems.

As timesheets and expense reports come in, Nace agents check each line item against the corresponding assignment. Rates, overtime rules, expenses, holiday pay, and other provisions are verified against the contract before the invoice reaches review.

The evidence stays connected to the calculation. Each invoice includes an audit trail showing the source data, the contract terms applied, and how the charge was calculated. Individual line items can be traced back to the relevant timesheet entry and contract clause.

Work that previously took hours or days can now be completed in seconds, while the team can review billing across thousands of invoices without losing the connection to the underlying documents.

What changed in the first eight weeks

Barton evaluated performance across 10,000 invoices reviewed end to end during the first eight weeks after launch, compared with the eight weeks before:

Billing built around the contract

For agencies, billing often depends on information spread across contracts, timesheets, expenses, and supporting documents. Nace brings those inputs into one workflow, keeping each invoice connected to the terms and evidence behind it.

Teams can handle higher billing volume with less manual reconciliation while maintaining a clear, auditable record of every charge.