Section 15. Acquisition costs in connection with the solicitation of subscribers, and the cost of administration shall at all times be limited to such amounts as the commissioner of insurance shall approve as adequate and reasonable, but in any event, such acquisition costs shall not exceed in any one year ten per cent of the earned subscription fees during that year, except that during the first five years after the issuance of a certificate of compliance by said commissioner such corporation may disburse not more than twenty per cent of such amount in each year.