In order to avoid or lessen the possibility and amount of excess deficit surcharges authorized by this chapter, the commissioner shall approve rates for policies issued by the association at least adequate to fund annual reinsurance above a self-insured retention of One Hundred Million Dollars ($100,000,000.00) that, combined with any readily available reserves of the association, is sufficient to cover at least the probable maximum losses from a storm expected to occur once every one hundred (100) years as predicted by a model or method approved by the commissioner for the properties insured by the association at the time the reinsurance was negotiated. The amount of reinsurance in the foregoing rate adequacy requirement shall increase every two (2) years by increasing the probable maximum loss by five (5) years, until such time as the probable maximum loss insured is for a storm expected to occur every one hundred fifty (150) years. The commissioner may approve rates in excess of the minimums required by this section as consistent with his duties and the insurance laws of the State of Mississippi. Any self-insured retention related to the purchase of reinsurance shall be subject to the prior approval of the commissioner.