Commencing October 1, 1996, each person whose employer participates in the Employees’ Retirement System pursuant to Section 36-27-6, whose effective date of retirement for purposes of receiving benefits from the Employees’ Retirement System is prior to October 1, 1996, and who is receiving or is entitled to receive a monthly allowance from the Employees’ Retirement System, and certain beneficiaries of deceased members and deceased retirees currently receiving survivor benefits, if the effective date of retirement or death for the deceased retiree or deceased member was prior to October 1, 1996, for purposes of receiving benefits from the Employees’ Retirement System, shall receive a cost-of-living increase of not less than twenty-five dollars ($25) per month and the increase shall be more if determined by the formula used in Section 36-27-130. Any employer may elect by July 1, 1997, to discontinue the cost-of-living increases paid to its retired employees and certain beneficiaries pursuant to this section effective October 1, 1997. Any employer participating under Section 36-27-6, may elect to come under this article at the beginning of any subsequent fiscal year and the employer shall not be required to pay this cost-of-living increase retroactively.