(a) DRC's can be added to the following PIA's when used in computing the following benefits:

1. (1) Tier I PIA used in computing a retirement employee annuity.
2. (2) Overall Minimum PIA used in computing a retirement employee annuity.
3. (3) Survivor Tier I PIA used in computing a widow(er), remarried widow(er) or surviving divorced spouse annuity based on age or disability.
4. (4) Employee RIB PIA used in computing a widow(er), remarried widow(er) or surviving divorced spouse annuity based on age or disability.
5. (5) RLS PIA used in computing the amount of the residual lump-sum payable (as explained in part 234 of this chapter).