(a) Amounts in the D.C. Federal Pension Fund shall be used:
(1) To make Federal benefit payments under this chapter;
(2) Subject to subsection (b) of this section, to cover the reasonable and necessary administrative expenses incurred by any person in administering the D.C. Federal Pension Fund and carrying out this subchapter;
(3) For the accumulation of funds in order to finance obligations of the Federal Government for future benefits; and
(4) For such other purposes as are specified in this chapter.
(b) The administrative expenses of the D.C. Federal Pension Fund shall be paid in accordance with an annual budget set forth by the Pension Fund Trustee which shall be subject to certification and approval by the Secretary.