(1) The board of trustees shall establish, in addition to the several benefits provided for, an additional and separate fund to be known as the "supplemental benefits fund" to provide for the payment of supplemental benefits, as hereinafter provided for employees of municipalities electing to participate in said fund.
(2) Any municipality which has elected to participate in this retirement system may elect to have the employees of the municipality participate in and be covered by the supplemental benefits fund. Such election is authorized to be made in any manner authorized by RCW
41.44.050, as now or hereafter amended, as it relates to participation in the system.
(3) A municipality which once elects to participate in the supplemental benefits fund shall never discontinue participation in the fund as to members who are covered in the fund.
(4) Membership in the fund shall be terminated by cessation of membership in the system.
(5) Each municipality which elects to participate in the supplemental benefits fund shall contribute to that fund, in addition to normal contributions and prior service contributions as required, such additional percentage of each payment of earnings as may be fixed by the board, on recommendation of the actuary, as necessary to accumulate the reserves needed to pay the anticipated benefit: PROVIDED, That the rate of contribution to the supplemental benefits fund shall be on the full compensation of the member.
(6) The supplemental benefit for covered employees shall be an allowance not to exceed fifteen percent of average final compensation payable at the time of retirement.
(7) Should the service of a member be discontinued by other than death or retirement, the benefits and privileges as provided by RCW
41.44.190 as now or hereafter amended, shall apply.
(8) A municipality which elects to participate in the supplemental benefits fund shall provide such benefits for all members employed by such city.