Commencing October 1, 2006, there is provided an increase in benefits to certain persons identified in this section who are currently receiving benefits whose effective date of retirement was prior to October 1, 2005, for purposes of receiving benefits from the Employees’ Retirement System, and to certain beneficiaries of deceased members and deceased retirees who are currently receiving survivor benefits if the effective date of retirement or death for the deceased member or retiree was prior to October 1, 2005, for purposes of receiving benefits from the Employees’ Retirement System shall receive the cost-of-living increase of two percent in their gross monthly benefit which the Legislature committed to in Section 14 of Act 2005-316, plus an additional five percent increase in their gross monthly benefit. The increase shall not be less than twenty-five dollars ($25) per month. The benefits provided in this section are limited to those retirees whose participation in the Employees’ Retirement System was based on Section 36-27-6, and whose employer at the time of retirement was a local board of education or a state-supported institution of higher education. The benefits granted in this section shall not apply to any other participants in the Employees’ Retirement System.