The amount of any cost-of-living increase or decrease in any year which is in excess of the maximum annual allowance adjustment of three percent provided in Section 2.124.1690 of this chapter shall be accumulated from year to year and included in the computation of increases or decreases in succeeding years. The provisions of this section shall be applied to the allowance of individual beneficiaries by classes based upon the fiscal year in which the member retired or died, so that each allowance shall have applied to it only such increase or decrease as shall have accumulated during or after the fiscal year in which they retired or died. The allowances payable to or on account of any retired or deceased person whose retirement or death shall have occurred prior to July 1, 1967, shall be grouped in the first such class. (Prior code § 34.09.902)