The supplement is computed as if an employee were age 62 and fully eligible for Social Security benefits when the supplement begins. The department first estimates what the full Social Security benefits for the employee would be. Then it calculates the amount of service under the FSPS and reduces the estimated full Social Security benefits accordingly. (If an estimated Social Security benefit at age 62 is $20,000 and the number of years under the FSPS is 20 years, the formula would be $20,000 divided by 40 times 20, or $10,000.)