(A) All requests for external review must be made in writing to the health carrier.
(B) A covered person or his authorized representative may make a request for an external review of an adverse determination or final adverse determination only when the amount payable for covered benefits is at least five hundred dollars.
(C) A covered person is not entitled to an external review of a retrospective review determination unless the covered person has exhausted the health carrier's internal appeal process and may be held financially responsible for the covered benefits.