appeal period or until approval by the board of the classification assigned. (1) No insurer may increase premiums for fire insurance based on a fire protection classification until the expiration of the thirty (30) day period for appeal by the fire protection district, municipality or locality, as provided in KRS 304.13-355. If an appeal is filed, no insurer may increase such premiums until approval of the fire protection classification by the commissioner. (2) If the commissioner's reassignment or modification of a fire protection classification results in lower fire insurance premiums, the appropriate insurers shall make any refunds of paid premiums due to customers within the affected fire protection district, municipality or locality. Such refunds shall be determined from the date the advisory organization or insurer last assigned or reassigned the classification appealed.