(1) (a) A vested tier one member who is not eligible for service retirement but has attained the age of 50 is eligible for an early retirement allowance.
(b) A vested tier two member who is not eligible for service retirement but has attained the age of 55 is eligible for an early retirement allowance.
(2) A member retiring early under subsection (1) must have terminated employment in all positions reportable to the retirement system and must file a written application with the retirement board.
(3) The early retirement allowance must be determined as prescribed in 19-20-804, with the exception that the allowance will be reduced using actuarially equivalent factors based on the most recent actuarial valuation of the system.