5 CFR §841.408

1. (a)Except as provided in paragraph (b) of this section and in § 841.412, normal cost percentages stated in a notice of normal cost percentages under § 841.407 will be effective at the beginning of the first full pay period of the first fiscal year that commences at least 3 months after the date of publication of the notice.
2. (b)The initial normal cost percentages will be effective at the beginning of the first pay period on or after January 1, 1987.