(a) The operating day of each flue-cured leaf tobacco warehouse shall not exceed the number of hours required to handle and sell adequately and efficiently the number of pounds or piles of tobacco allowed to be sold each day.

(b) The operating week of such warehouse shall be limited to five actual selling days, provided that no sale shall be held on Saturday or Sunday.

(c) All tobacco warehouses shall be closed on Sunday for the purpose of receiving, unloading, weighing, or placing tobacco on a warehouse floor between the hours of 12:01 A.M., Sunday and 12:01 A.M., Monday.