(

a) The board of retirement shall, before April of each year, determine whether there has been an increase or decrease in the cost-of-living as provided in this section. Notwithstanding

Section or any other provision of this chapter, every retirement allowance, optional death allowance, or annual death allowance payable to or on account of any member, of this system or a superseded system, who retires or dies or who has retired or died shall, as of April 1st of each year, be increased or decreased to the nearest one-tenth of percent, by percent of the annual increase or decrease in the cost-of-living as of January 1st of each year as shown by the then current (year ending December) Bureau of Labor Statistics’ Consumer Price Index for All Urban Consumers for the United States City Average, except that no decrease shall reduce the allowance below the amount being received by the member or his or her beneficiary on the effective date of the allowance. (

b) The allowance shall be increased a minimum of percent in any year in which the board’s determination of cost-of-living change of allowance would result in less, provided that the member or beneficiary has an accumulated unpaid cost-of-living account sufficient to provide the percent increase. (

c) When this

section becomes applicable in a county, the accumulated unpaid cost-of-living account of each retired member or beneficiary under the superseded

Section 31870, shall be transferred to a like account under this section. Thereafter, no increases shall be made to such account. (

d) The board of retirement may adopt this

section to be effective in lieu of

Section 31870, provided, that no increase in unfunded actuarial liability nor in current member or employer contributions to the system are required as a result of the adoption and is so attested by an enrolled actuary. After adoption, the effective date for increases or decreases in allowances pursuant to this

section shall be the next succeeding April 1. (

e) This

section shall apply only in a county of the first class, as established by Sections and 28022, as amended by

Chapter of the Statutes of 1971.