OIG: WPS overpaid providers $140K on 138 Part B lines that paid more than the charge billed

Medicare is not supposed to pay a provider more than the provider asked for. HHS-OIG posted audit A-07-24-04138 on July 22, 2026: of 801 Part B outpatient claim lines that Wisconsin Physicians Service Insurance Corporation (WPS) paid providers in excess of their billed charges, 138 were incorrect and produced at least $140,182 in overpayments. It's a small-dollar finding with a plain lesson for anyone who keys a charge.

What OIG actually looked at

This is a followup in a long-running OIG series that checks a narrow question: when a Medicare administrative contractor pays a provider more than the provider billed for an outpatient service, was that payment correct? WPS is the MAC under review here. OIG pulled claim lines where WPS paid above the billed charge and asked whether each was right.

The audit period ran January 1, 2022 through December 31, 2023. From the lines where the payment exceeded the charge, OIG selected 801, and 138 of them were incorrect overpayments totaling at least $140,182.

Why a payment above the charge gets flagged

Medicare pays the lower of two numbers: the charge the provider submits, or the fee schedule amount for that service. The submitted charge is a ceiling. If your billed charge lands below the fee schedule amount, the payment should cap at what you billed, not at the higher schedule figure. So a line that pays out above the submitted charge is the flag OIG pulls on. It selected 801 WPS lines that paid over the billed charge, reviewed them, and confirmed 138 were genuine overpayments.

That's why a data-entry slip cuts both ways. Key a charge too low and you cap your own payment below what the service is worth. Key it in a way the contractor's edits don't catch, and the system can pay above the charge, which becomes money the MAC has to claw back later.

Where the errors came from

OIG didn't dispute that the services happened, and it didn't allege fraud. Providers attributed the overpayments to clerical errors and problems with their billing systems. WPS had system edits meant to flag line-item payments that exceed billed charges, but OIG found those edits, and WPS's review of the payments they flagged, didn't always catch the lines that were wrong.

The 31 lines nobody could document

Separate from the overpayments, OIG flagged 31 claim lines worth $76,640 where providers received Part B payments but no supporting documentation existed. The two providers responsible for those lines couldn't be reached during the audit, so those lines were never resolved. OIG told WPS to locate the records, decide whether the lines were supported, and recover anything that was not.

That is the same failure mode behind insufficient-documentation Medicare denials: a service can be perfectly legitimate and still become an overpayment the moment the record cannot be produced on request.

What OIG told WPS to do

OIG made five recommendations. WPS should confirm it recovered the $140,182, locate the documentation for the $76,640 in undocumented lines and recover any overpayments there, work with providers on the 15 lines for which WPS had not yet processed a corrected claim, enhance the system edits that catch payments above billed charges, and expand provider education. WPS concurred with all five and described steps it has taken or plans to take.

The claim lines are from 2022 and 2023, so this is not a notice of new exposure. What's current is the fix. If you bill outpatient Part B in a WPS jurisdiction, the enhanced edits and the education are coming, and the cheapest way to stay clear of both is to make sure your billed charges and your documentation are right before the claim goes out. The related Novitas nursing home Part B audit is the same OIG playbook aimed at a different service set.