Only those who retired from state employment before June 1, 2005, and returned to state employment before September 1, 2005, are eligible for longevity pay. In this case, the longevity pay is equal to the amount they were entitled to receive immediately before September 1, 2005. The rate will not change regardless of the employee’s subsequent state service months. No other return-to-work retirees are eligible for longevity pay.