2. Service before becoming a member. A member who served as a full-time active duty member of the armed forces before becoming a member of the retirement system is entitled to service credit for the period of time he served in the armed forces, under the following terms and conditions.

A. Except as provided in paragraph G, on the date of retirement, the member must have at least 15 years of creditable service.

C. The member must have separated from the armed forces under conditions other than dishonorable.

D. Except as provided in paragraph E, the member must have begun membership before January 1, 1976.

E. Except as provided in paragraph G, a member who served in the armed forces during any federally recognized period of conflict, as defined in Title 37-B, section 504, subsection 4, paragraph A-1, subparagraph (3), is entitled to service credit under this subsection.

F. Upon complete payment of the back contributions under section 17713, the member shall be granted service credit for the period of time for which the contributions have been made. Upon making partial payment of the back contributions under section 17713, the member shall be granted service credit on a pro rata basis in accordance with rules adopted by the board.

G. A member who fails to meet one or more of the terms and conditions required under paragraphs A, D and E may purchase service credit as provided in this paragraph. The member must have at least 5 years of creditable service and, before any retirement benefit becomes effective for that member, must pay into the Members' Contribution Fund, by a single direct payment or annual direct payments to the retirement system, an amount that, together with regular interest on that amount, is the actuarial equivalent, at the effective date of the retirement benefit, of the portion of the retirement benefit based on the additional creditable service. Annual direct payments must be made in accordance with section 17701, subsection 4. Any member who purchases service credit under this paragraph who subsequently, without inclusion of the purchased service credit and prior to retirement, meets the terms and conditions of paragraphs