(a) Nothing contained in this part shall be construed as having the effect of superseding or amending the provisions of any regulations issued or approved by the Secretary pursuant to the Act of December 23, 1944, as amended (67 Stat. 61).

(b) The Secretary may waive, withdraw, or amend at any time or from time to time any or all of the provisions of the regulations of this part.

(c) Implementing regulations within the framework of this circular will be issued by the Fiscal Assistant Secretary of the Treasury. All communications pertaining to the administration of the provisions of this part shall be directed to the Fiscal Assistant Secretary.