((a)) ** .—** The Superintendent of Documents, under the direction of the Director of the Government Publishing Office, may charge reasonable fees for use of the directory and the system of access provided for under section 4101, except that use of the directory and the system shall be made available to depository libraries without charge. The fees received shall be treated in the same manner as moneys received from sale of documents under .

((b)) ** .—** The fees charged under this section shall be set so as to recover the incremental cost of dissemination of the information involved, with the cost to be computed without regard to .