Except as otherwise provided in this chapter, or by firmly established trade custom and practice, or exempted by a rule of the board:
provided that liquid commodities shall be sold by weight and commodities not in liquid form shall be sold by measures other than weight, when such methods give accurate information as to the quantity of commodity sold. All methods of sale shall provide accurate and adequate quantity information that permits the buyer to make price and quantity comparisons. The board may adopt such reasonable rules as may be necessary to assure that the measure of any commodity for sale reflects accurate information and fair measurement practices to all concerned.
HRS § 486-110