Amounts chargeable to and available from Federal sources for inpatient and outpatient services provided through Saint Elizabeths Hospital as authorized by , 196, 211, 212, 222, 253, and 324; ; and and 251 shall not exceed the estimated total cost of such services as computed using only the proportionate amount of the direct Federal subsidy appropriated under this heading.24 U.S.C. 191131 U.S.C. 153542 U.S.C. 249