Mid-Year MCS-150 Audit Findings - Common Errors

What changed

FMCSA released mid-year MCS-150 audit findings on January 18, 2026 covering audits conducted October-December 2025. Top three deficiency categories: stale power-unit counts (38% of audited carriers had a count off by more than 20%), wrong vehicle-miles-traveled (VMT) reporting (24%), and expired or mismatched insurance certificate dates (12%).

The deficiency rate is high because MCS-150 is a self-reported form and many carriers treat the biennial filing as a perfunctory click-through rather than a meaningful update.

Why power-unit count matters

The power-unit count drives several downstream calculations: UCR bracket fee, IFTA decal count, and CSA percentile normalization. A carrier reporting 4 power units while actually operating 8 is potentially under-paying UCR and being mis-grouped in CSA percentile rankings.

During a compliance review, the auditor cross-checks MCS-150 power-unit count against the IFTA decal application, IRP cab card count, and BMC-91 schedule. Mismatches across these documents are a leading indicator of broader compliance laxity.

How to fix discrepancies

Most carriers don't need to wait for the biennial cycle to update MCS-150 - interim updates can be filed any time through the FMCSA portal. The interim update is a no-fee filing that just updates the system of record.

Practical recommendation: trigger an MCS-150 interim update whenever your fleet size changes by more than 25% or your operations type materially changes (e.g., starting hazmat operations).

What to do next

Pull your MCS-150 from FMCSA SAFER. Verify power-unit count, driver count, and operations type. If anything is materially stale, file an interim update through fastmcs150filing.com or the FMCSA portal.