A claim of the United States against a person arising out of an erroneous payment of any pay or allowances, other than travel and transportation expenses and allowances, on or after July 25, 1974, to the Vice President, a Senator, or to an officer or employee whose pay is disbursed by the Secretary of the Senate, the collection of which would be against equity and good conscience and not in the best interests of the United States, may be waived in whole or in part by the Secretary of the Senate. An application for waiver shall be investigated by the Financial Clerk of the Senate who shall submit a written report of his investigation to the Secretary of the Senate. An application for waiver of a claim in an amount aggregating more than $1,500 may also be investigated by the Comptroller General of the United States who shall submit a written report of his investigation to the Secretary of the Senate.