When two or more freight rates are named for carriage of goods of the same description over the same route and under similar conditions, and the application is dependent upon the quantity of goods shipped, the total freight charges assessed against the shipment shall not exceed the total charges computed for a larger quantity. Provided, however, that the rate noted alongside a qualification specifying a required minimum quantity, either weight or measurement per container or in containers will be applicable to the contents of the containers, provided the minimum set forth is met or exceeded. At the Shipper's option, a quantity less than the minimum level may be freighted at the lower rate, provided the weight or measurement declared for rating purposes is increased to the minimum level.