(a) Commencing October 1, 1998, any retired employee who retired from a city, town, county, or public or quasi-public organization of the state before the city, town, county, or public or quasi-public organization of the state became a member of the Employees' Retirement System, and who is receiving a monthly benefit prior to October 1, 1998, administered by the Employees' Retirement System, and whose years of creditable service has not been made known to the Employees' Retirement System, may receive an increase in benefits in the amount of sixty dollars ($60) per month if the monthly benefit is five hundred dollars ($500) or less; ninety dollars ($90) per month if the monthly benefit is more than five hundred dollars ($500) but less than one thousand dollars ($1,000); one hundred twenty dollars ($120) per month if the monthly benefit is more than one thousand dollars ($1,000) but less than fifteen hundred dollars ($1,500); one hundred fifty dollars ($150) per month if the monthly benefit is more than one thousand five hundred dollars ($1,500) but less than two thousand dollars ($2,000); one hundred eighty dollars ($180) per month if the monthly benefit is two thousand dollars ($2,000) but less than two thousand five hundred dollars ($2,500); and two hundred ten dollars ($210) per month if the monthly benefit is more than twenty-five hundred dollars ($2,500), provided the retired employee retired prior to October 1, 1998, and the employer decides to come under the provisions of this article.

(b) Retired local public agency employees who retired prior to membership of the employer in the Employees' Retirement System and whose creditable service records have been received by the Employees' Retirement System shall receive an increase based on the formula in Section 36-27-140 provided the employer elects to fund the increase.