Requesters seeking an appeal of the FOIA Office's fee or fee waiver determination must send a written appeal to the Managing Director within 90 calendar days. The Managing Director will determine whether to grant or deny any appeal made pursuant to §801.21 within 20 days (excluding Saturdays, Sundays, and legal public holidays) after receipt of such appeal, except that this time limit may be extended for as many as 10 additional days (excluding Saturdays, Sundays, and legal public holidays), in accordance with §801.23.