(1) Except as provided in subsection (2), a vested member who becomes disabled must be granted a disability retirement benefit that is the actuarial equivalent of the service retirement benefit under 19-8-603 standing to the member's credit at the time of the member's disability retirement.
(2) A vested member who becomes disabled as a direct result of the member's service in the line of duty:
(a) before completing 20 years of membership service must receive a disability retirement benefit equal to one-half the member's highest average compensation; or
(b) after completing 20 years or more of membership service must receive a disability retirement benefit equal to 2.5% of the member's highest average compensation for each year of service credit.