(a) Employee annuity payable for part of a month. If an employee annuity begins after the first day of the month, the O/M amount payable for the partial month is
1/30 of the monthly rate times the number of days in the partial month.
(b) Spouse annuity payable for part of a month—(1) Spouse not included in O/M before beginning date of spouse annuity and O/M applies as of the spouse annuity beginning date. If a spouse annuity begins after the first day of a month, and the spouse is not includable in the O/M before the beginning date of the spouse annuity, and the O/M rate paid to the family group, including the spouse, as of the spouse annuity beginning date exceeds the amounts payable using the benefit formulas under the Railroad Retirement Act, the amount payable to the spouse for the partial month is
1/30 of the spouse's share of the O/M rate times the number of days in the month beginning with the spouse's annuity beginning date. In such a case, if the employee annuity is payable from the first day of the month, the amount payable to the employee is:
(i) One-thirtieth of the higher of the railroad formula or the O/M rate, without the spouse included, times the number of days in the month before the spouse annuity begins, plus
(ii) One-thirtieth of the employee's share of the O/M rate, with the spouse included, times the number of days in the month beginning with the spouse's annuity beginning date.
(2) Spouse included in O/M before beginning date of spouse annuity and the O/M continues to apply. If a spouse annuity begins after the first day of a month, and the spouse is includable in the O/M before the beginning date of the spouse annuity, and the O/M rate paid to the family group, including the spouse, as of the spouse annuity beginning date continues to exceed the amounts payable using the benefit formulas under the Railroad Retirement Act, the amount payable to the spouse for the partial month is
1/30 of the spouse's share of the O/M rate times the number of days in the month beginning with the spouse's annuity beginning date. In such a case, if the employee annuity is payable from the first of the month, the amount payable to the employee is:
(i) One-thirtieth of the O/M rate, with the spouse included, times the number of days in the month before the spouse annuity begins; plus
(ii) One-thirtieth of the employee's share of the O/M rate, with the spouse included, times the number of days in the month beginning with the spouse's annuity beginning date.
(3) O/M rate applies before beginning date of spouse annuity and the railroad formula applies as of the spouse annuity beginning date. If a spouse annuity begins after the first day of a month and the O/M rate applies to the family group, with or without the spouse included, before the beginning date of the spouse annuity, and the O/M rate paid to the family group, including the spouse, as of the spouse annuity beginning date is less than the amounts payable using the formulas under the Railroad Retirement Act, the amount payable to the spouse for the partial month is
1/30 of the spouse's railroad formula rate times the number of days in the month beginning with the spouse's annuity beginning date. In such a case, if the employee annuity is payable from the first day of the month, the amount payable to the employee is:
(i) One-thirtieth of the O/M times the number of days in the month before the spouse annuity begins; plus
(ii) One-thirtieth of the employee's railroad formula rate times the number of days in the month beginning with the spouse's annuity beginning date.