5 CFR §841.412

1. (a)If the Board finds that a different normal cost is warranted based on an agency appeal, it will establish a single agency rate for the category of employees in that agency.
2. (b)The single agency rate will be effective at the beginning of the first pay period beginning 30 days after the date of the Board's decision.
3. (c)A single agency rate may be higher or lower than the published normal cost percentage and will remain in force for not less than 3 years.
4. (d)After a single agency rate has been in force for at least 3 years, OPM may—
   1. (1)Require, no more often than annually, that the agency justify continuation of the rate; and/or
   2. (2)When it publishes a notice of normal cost percentages under § 841.407, terminate the single agency rate.