(a) An assistant prosecutor accrues lifetime service credit for the period in which the assistant prosecutor serves as a full-time, part-time, or temporary assistant prosecutor.
(b) An assistant prosecutor who is on leave without pay for an entire calendar month does not accrue lifetime service credit for the month.
(c) An assistant prosecutor who simultaneously holds two or more positions that each accrue lifetime service credit accrues credit for only one of the positions.
(d) An assistant prosecutor who begins working on the first workday of a month in a position that accrues lifetime service credit is considered to have begun working on the first day of the month.