A member may make the irrevocable election under this section no later than six months after attaining thirty years of service. The election shall become effective at the beginning of the calendar month following department receipt of employee notification.

(1) The sum of member contributions made for periods of service after the effective date of the election plus seven and one-half percent interest shall be paid to the member at retirement without a reduction in the member's monthly retirement benefit as determined under RCW 41.32.498.

(2) Upon retirement, the member's benefit shall be calculated using only the earnable compensation credited prior to the effective date of the member's election. Calculation of the member's average earnable compensation shall include eligible cash outs of annual leave based on the member's salary and leave accumulations at the time of retirement, except that the amount of a member's average earnable compensation cannot be higher than if the member had not taken advantage of the election offered under this section.

(3) Members who have already earned thirty years of service credit prior to July 25, 1999, may participate in the election by notifying the department in writing of their intention by December 31, 1999.

The department shall continue to collect employer contributions as required in RCW 41.45.060.