“Notwithstanding any other provision of law, the Administrator of General Services shall delegate the authority to procure automatic data processing equipment for the Tax Systems Modernization Program to the Secretary of the Treasury: Provided, That the Director of the Office of Management and Budget shall have the authority to revoke such delegation upon the written recommendation of the Administrator that the Secretary’s actions under such delegation are inconsistent with the goals of economic and efficient procurement and utilization of automatic data processing equipment: Provided further, That for all other purposes, a procurement conducted under such delegation shall be treated as if made under a delegation by the Administrator pursuant to [former] 40 U.S.C. 759.”