United States Postal Service's CSRS Obligation Modification Act of 2010 - Prescribes the "average pay" and the appropriate percentage thereof to be used in determining annuities for civilian employment with the United States Postal Service (USPS) for purposes of provisions relating to future benefits attributable to such employment in order to calculate the amount of any Postal surplus or supplemental liability under the Civil Service Retirement System.
Requires the Office of Personnel Management (OPM): (1) within six months after enactment of this Act, to determine (or, if applicable, redetermine) the amount of such surplus or liability as of the close of the most recently ending fiscal year using the methodology required under this Act; and (2) if the result is a surplus, to transfer the surplus amount to the Postal Service Retiree Health Benefits Fund.