(a-5) For the purposes of computing service for academic years for any participant, the following schedule shall govern: one month of service means a calendar month during which a participant (i) qualifies as an employee under Section 15-107 and contributes to the System, and (ii) receives any earnings as an employee; 8 or more months of service during an academic year shall constitute a year of service; 6 or more but less than 8 months of service during an academic year shall constitute 3/4 of a year of service; 3 or more but less than 6 months of service during an academic year shall constitute 1/2 of a year of service; and one or more but less than 3 months of service during an academic year shall constitute 1/4 of a year of service. No more than one year of service may be granted per academic year, regardless of the number of hours or percentage of time worked. This subsection (a-5) applies to all service periods of a member who is a participant on or after September 1, 2024; except that such changes shall not apply to service periods that were subject to: (1) a purchase under subsection (i) of Section 15-107, subsection (c) of Section 15-113.1, or Section 15-113.2, 15-113.3, 15-113.5, 15-113.6, 15-113.7, or 15-113.11; (2) a repayment of a refund under subsection (b) of Section 15-154 or a distribution under subsection (j) of Section 15-158.2; or (3) a transfer under Section 15-113.10, 15-134.2, or 15-134.4 if payment for such purchase, repayment, or transfer commenced prior to September 1, 2024.