Persons excluded from membership pursuant to Sections 22601.5, 22602, and 22604 may elect membership in the Defined Benefit Program at any time while employed to perform creditable service subject to coverage under that program. The election shall be in writing on a form prescribed by this system and shall be filed in the office of this system prior to submission of contributions. The election is irrevocable and shall remain in effect until the member terminates employment and receives a refund of accumulated retirement contributions. The amendments to this section enacted during the 1995–96 Regular Session shall be deemed to have become operative on
July 1, 1996.