Unless a foundation member's required beginning date for retirement occurs first, the early or normal retirement benefit of a foundation member is effective in accordance with whichever of the following is last:
The last payment of the member's benefit is for the month in which the member's death occurs.
Any foundation member who fails to make a timely application for retirement benefits may receive three months of benefits retroactive from the effective date of the member's retirement benefit. However, no foundation member may receive any retroactive benefits for any period of time before the first day of the month following the date on which the member's contributory service terminated.
SDCL 3-12C-1113