Proceeds from reimbursements under this section shall be deposited in the Treasury and may be withdrawn by the Secretary to pay directly the cost of such work or services, to repay or make advances to appropriations of funds which will initially bear all or a part of such cost, or to refund excess sums when necessary. Such payments may be credited to a working capital fund otherwise established by law, including the fund established pursuant to section
7263 of this title, and used under the law governing such fund, if the fund is available for use by the Department for performing the work or services for which payment is received.