843.503—Commencing and terminating dates.
(b)
An annuity under this subpart terminates on the last day of the month before the insurable interest beneficiary dies.
(c)
A survivor annuity accrues on a daily basis, one-thirtieth of the monthly rate constituting the daily rate. An annuity does not accrue for the 31st day of any month, except in the initial month if the survivor's (of a deceased employee) annuity commences on the 31st day. For accrual purposes, the last day of a 28-day month constitutes 3 days and the last day of a 29-day month constitutes 2 days.