Insurance policies; appropriate reduction in premiums.

A. Any rates, rating schedules or rating manuals for the liability, personal injury protection and collision coverages of a motor vehicle insurance policy submitted to or filed with the superintendent of insurance shall provide for an appropriate reduction in premium charges for a three-year consecutive period for such coverages when the principal operator of the covered vehicle: (1) is an insured driver fifty-five years or older; and (2) has successfully completed a motor vehicle accident prevention course approved by the traffic safety bureau of the state highway and transportation department. B. Any discount used by the insurer pursuant to this section shall be presumed appropriate unless credible data demonstrates otherwise.