(b)
The action of the Secretary or his designee in allowing or denying a payment under this subchapter is—
(1)
final and conclusive for all purposes and with respect to all questions of law and fact; and
(2)
not subject to review by another official of the United States or by a court by mandamus or otherwise.
Credit shall be allowed in the accounts of a certifying or disbursing official for payments in accordance with that action.