If the hearing is held by a hearing examiner such hearing examiner shall either make an initial decision, if so authorized, or certify the entire record including his recommended findings and proposed decision to the responsible GSA official for a final decision, and a copy of such initial decision or certification shall be mailed to the applicant or recipient. Where the initial decision is made by the hearing examiner the applicant or recipient may within 30 days of the mailing of such notice of initial decision file with the responsible GSA official his exceptions to the initial decision, with his reasons therefor. In the absence of exceptions, the responsible GSA official may on his own motion within 45 days after the initial decision serve on the applicant or recipient a notice that he will review the decision. Upon the filing of such exceptions or of such notice of review the responsible GSA official shall review the initial decision and issue his own decision thereon including the reasons therefor. In the absence of either exceptions or a notice of review the initial decision shall constitute the final decision of the responsible GSA official.