((a)) The cost of publishing the Federal Register and the Code of Federal Regulations, and, except as provided in subsection (b), other expenses incurred by the Government Publishing Office in carrying out the duties placed upon it by this chapter shall be charged to the revolving fund provided in section 309. Reimbursements for such costs and expenses shall be made by the Federal agencies and credited, together with all receipts, as provided in section 309(b).

((b)) The cost of publishing all other publications of the Federal Register program, and other expenses incurred by the Government Publishing Office in connection with such publications, shall be borne by the appropriations to the Government Publishing Office and the appropriations are made available, and are authorized to be increased by additional sums necessary for the purposes, the increases to be based upon estimates submitted by the Director of the Government Publishing Office.