This section applies to the State Police Retirement System. Except as provided in § 24–401.1(k) of this article, the Board of Trustees shall grant a special disability retirement allowance to a member if: the member is totally and permanently incapacitated for duty arising out of or in the course of the actual performance of duty without willful negligence by the member; and the medical board certifies that: the member is totally incapacitated, either mentally or physically, for the further performance of duty; the incapacity is likely to be permanent; and the member should be retired. Except as provided in subsection (d) of this section, a special disability retirement allowance equals the lesser of: the member’s average final compensation; or the sum of: an annuity that is the actuarial equivalent of the member’s accumulated contributions at retirement; and a pension equal to two–thirds of the member’s average final compensation. This subsection applies to a member who is at least normal retirement age. A special disability retirement allowance equals the greater of: a normal service retirement allowance; or a special disability retirement allowance computed in accordance with subsection (c) of this section.