(a) Price per dozen for commodities whose net quantity is commonly expressed by half dozen, dozen or a combination thereof, provided that the same unit of measure is used for the same commodity in all sizes.

(b) Price per 100 square feet, and the ply count, if any, for commodities whose net quantity is expressed in units of areas where the net quantity exceeds 100 square feet, provided that the same unit of measure is used for the same commodity in all sizes.

(c) Price per gallon in alternative to price per pint or quart for commodities whose net quantity is stated in fluid ounces, pints, quarts, or gallons, provided that the same unit of measure is used for the same commodity in all sizes.