Application for an Open Cargo Policy shall be made by filing Form MA-301, prescribed in §308.521, with the underwriting agent of MARAD. The application shall state the applicant's name and address; the person or persons to whom loss shall be payable; the nature and geographic scope of the shipments to be covered under the policy which shall not be broader than the coverage authorized in §308.501; the requested effective date, which shall not be earlier than the date of the completion of the requirements for the issuance of the policy; and the basis of valuation to be incorporated in the policy. An applicant may specify one basis of valuation for imports and another for exports, and he may specify different bases of valuation for different commodities or voyages, provided that each basis of valuation specified by the applicant shall define the value by the use of facts which existed prior to the date of the shipment and which are readily ascertainable by either party after the safe arrival or loss of the shipment.