A licensed warehouseman shall not make any unreasonable, exorbitant, or discriminatory charge for services rendered. Before a license to conduct a warehouse is granted under the act, the warehousemen shall file with the Department a copy of his rules, if any, and a schedule of the charges to be made by him if licensed. Effective at the beginning of any cotton season, a licensed warehouseman may change his rate of charges for storage and other services, and the new rates may apply to all cotton then in storage as well as cotton received thereafter. At or before the beginning of each season every licensed warehouseman shall file with the Department a copy of his rules, if any, and of his schedule of charges for the ensuing season. Should a licensed warehouseman wish to make changes in his rates to become effective at any time other than at the beginning of a season, he shall file with the Department an amended schedule showing the contemplated changes, accompanied by a statement setting forth the reasons therefor. No increase in the storage rate shown in such an amended schedule shall apply to cotton in storage at the time the changes become effective. A licensed warehouseman may demand payment of all accrued charges at the close of each cotton season. If, upon demand, the owner of the cotton refuses to pay such charges at the end of a season, the warehouseman may take such action to enforce collection of his charges as is permitted by the laws of the State in which the warehouse is located. Each licensed warehouseman shall keep a copy of his current rules and schedule of charges exposed conspicuously in the place prescribed by § 735.6 and at such other place accessible to the public as the Secretary or his designated representative may from time to time designate. For the purposes of this section the cotton season shall commence, with respect to each warehouse, at such time not later than September 1 of each year, as the operator of the warehouse shall select, and he shall notify the Department in writing not less than five days next preceding the date selected.