(a) The board shall annually adopt as a plan amendment with respect to the Defined Benefit Program the rate of credited interest to be credited to members’ accumulated retirement contributions for service performed after June 30, 1935, and the accumulated annuity deposit contributions excluding all accumulated contributions while being paid as disability allowances, family allowances, and retirement allowances.
(b) The board shall credit interest to all other accumulated reserves at the actuarially assumed interest rate.