An employee serving under an overseas limited appointment of indefinite duration or an overseas limited term appointment in a position subject to the General Schedule, is eligible for within-grade increases in accordance with subpart D of part 531 of this chapter. (5 U.S.C. 3301, 3302, E.O. 10577, 3 CFR, 1954-1958 Comp., p. 218, as amended by E.O. 10641, 3 CFR, 1954-1958 Comp., p. 274)