41 C.F.R. § 105-54.303
(g) The pay of each staff member of an advisory committee is fixed at a rate of the General Schedule, General Management Schedule, or Senior Executive Service pay rate in which the staff member's position would be placed (5 U.S.C. Chapter 51). GSA cannot fix the pay of a staff member higher than the daily equivalent of the maximum rate for GS-15 unless the Administrator decides that under the General Schedule, General Management Schedule, or Senior Executive Service classification system, the staff member's position should be higher than GS-15. The Administrator must review this decision annually.