(A) If no survivor annuity under section 8442 is to be provided for, but one or more survivor annuities under section 8445 involving a total of less than the entirety of the amount referred to in subsection (b)(2) of such section are to be provided for, the annuity of the annuitant involved (as computed under section 8415, or under section 8452 (including subsection (a)(2) of such section, if applicable)) or one-half of the annuity, if jointly designated for this purpose by the employee or Member and the spouse of the employee or Member under procedures prescribed by the Office of Personnel Management, shall be reduced by an appropriate percentage determined under subparagraph (B).

(B) The Office shall prescribe regulations under which an appropriate reduction under this paragraph, not to exceed a total of 10 percent, shall be made.

(A) after the death of the spouse; or

(B) after the dissolution of the spouses marriage to the employee or Member, except that an appropriate reduction shall be made thereafter if the spouse is entitled, as a former spouse, to a survivor annuity under section 8445.

(A) another former spouse who is entitled to a survivor annuity under section 8445;

(B) a current spouse to whom the employee or Member was married at the time of retirement and with respect to whom a survivor annuity was not waived under section 8416 (a) (or, if waived, with respect to whom an election under section 8416 (d) has been made); or

(C) a current spouse whom the employee or Member married after retirement and with respect to whom an election has been made under subsection (b) or (c) of section 8416.