(1) The pension benefit payable pursuant to this part may commence on:
(a) the first day of the month following the eligible member's last day of service; or
(b) the first day of a later month following filing of the written application.
(2) The benefit may not commence prior to the date of the board's decision regarding any disputed credited years of service pursuant to 19-17-201.
(3) Monthly survivorship benefits payable pursuant to this part must commence the first day of the month following the day of death of the member.