How does HRSA define and verify 340B manufacturer overcharges during audits?

HRSA defines a 340B manufacturer overcharge as any sale where the price exceeds the legal ceiling, regardless of intent. Manufacturers calculate this ceiling using Medicaid Drug Rebate Program data, and HRSA verifies it through AMP and Unit Rebate Amount crosschecks. Covered entities must document invoice comparisons, flag discrepancies, and maintain proof for audits.