In any case in which—

the rate of pay of, or any maximum or minimum rate of pay with respect to—

(A) any employee described in subparagraph (1) or subparagraph (2) of section 1841 of this title, or

(B) the position of such employee, or

(C) any class or group of such employees or positions,

(2) the rate so referred to or provided is a basic rate with respect to which additional pay is provided by law;

(Pub. L. 91–510, title IV, § 483, Oct. 26, 1970, 84 Stat. 1196.)