For purposes of this section, “lump-sum credit” does not include—

The amount by which the lump-sum credit attributable to service performed before the annuitant's first retirement was reduced by annuity payments that were not reimbursed by the employing agency under section 8344(a) of title 5, United States Code, or

Any part of the lump-sum credit attributable to service performed before the annuitant's first retirement that has already been paid to the annuitant pursuant to an election or an alternative form of annuity.

An annuitant who meets the requirements for a redetermined annuity under subpart H, and who meets all requirements of § 831.2203, may elect an alternative form of annuity.

To compute the beginning rate of the redetermined annuity payable to an annuitant who elects an alternative form of annuity, OPM will first compute the monthly rate payable under subchapter III of chapter 83 of title 5, United States Code, including all reductions provided under the subchapter other than those in section 8343a. That monthly rate is then reduced by the sum of—

Any reduction that was computed under § 831.2205 at the time of the annuitant's prior retirement, increased by—

All cost-of-living adjustments under section 8340 of title 5, United States Code that applied to the annuitant before the commencing date of the redetermined annuity, and

An amount equal to the annuitant's lump-sum credit, divided by the present value factor for the annuitant's attained age on the date the redetermined annuity commences.

The beginning rate of a redetermined annuity payable to an annuitant who does not elect, or is not eligible to elect, an alternative form of annuity will be reduced in accordance with paragraph (c)(1) of this section.