(a) A rate of basic pay under this subpart must be—

1. (1) Not less than 120 percent of the minimum rate of basic pay payable for GS-15 of the General Schedule, and

2. (2) Not greater than—

   1. (i) The rate of basic pay payable for level III of the Executive Schedule (EX-III), or
   2. (ii) In the case of an SL or ST employee who is covered by a certified performance appraisal system or whose established rate of basic pay is preserved under § 534.509, the rate of basic pay payable for level II of the Executive Schedule (EX-II).

(b) An agency may not set or adjust the rate of basic pay for an SL or ST employee higher than the maximum in—

1. (1) Paragraph (a)(2)(i) of this section (i.e., EX-III) when the SL or ST employee is covered by a performance appraisal system that is not certified or when the SL or ST employee is not subject to a performance appraisal system, except as provided in § 534.509; or
2. (2) Paragraph (a)(2)(ii) of this section (i.e., EX-II) when the SL or ST employee is covered by a certified performance appraisal system.