What is the USC that covers overpayments from OWCP and SSA

You are incorrect in your understanding. Pursuant to 5 U.S.C. 8116(d), a beneficiary may receive compensation under the FECA for either the death or disability of an employee concurrently with benefits under title II of the Social Security Act on account of the age or death of such employee. However, this provision of the FECA also requires OWCP to reduce the amount of any such compensation by the amount of any Social Security Act benefits that are attributable to the Federal service of the employee. 5 USC Sec. 8116(d)(2) requires that all benefits paid by the Department of Labor (DOL) for work related injuries and deaths shall be offset by the amount of any concurrent Social Security retirement or survivor benefit which is attributable to Federal service. DOL imposes this offset against the FERS/FECA benefit when the beneficiary receives both a FERS/FECA benefit and an SSA retirement or survivor benefit and both are based in part on the same earnings. The offset is based on information provided by SSA. This offset can only occur with covered Federal earnings for 1984 or later. Offset does not apply to the DOL benefit if the SSA benefit is a disability benefit. All of these cases are processed by the Office of International Operations regardless of SSN or other jurisdictional rules. The information forwarded to DOL is for their offset use only. It does not affect SSA's records or SSA benefits.