no list shall involve funds that are not available for obligation. 186. Rebates, refunds, incentive payments, minor fees and other funds received by the Department of Transportation from travel management centers, charge card programs, the subleasing of building space, and miscellaneous sources are to be credited to appropriations of the Department of Transportation and allocated to elements of the Department of Transportation using fair and equitable criteria and such funds shall be available until expended. 187. Amounts made available in this or any prior Act that the Secretary determines represent improper payments by the Department of Transportation to a third-party contractor under a financial assistance award, which are recovered pursuant to law, shall be available— (1) to reimburse the actual expenses incurred by the Department of Transportation in recovering improper payments: Provided , That amounts made available in this Act shall be available until expended