. "After the Federal District Court invalidated the 1981 rule in a suit brought by various hospitals in the District of Columbia, and the Secretary settled the hospitals' cost reimbursement reports by applying the pre-1981 wage-index method, the Secretary in 1984 reissued the 1981 rule and proceeded to recoup the sums previously paid to the hospitals, including respondents, as a result of the Distric" . . .