23. (1) A licensee shall not, in making any agreement for the supply of energy, show undue preference to any person, but may, save as aforesaid, make such charges for the supply of energy as may be agreed upon, not exceeding the limits imposed by his license. (2) No consumer shall, except with the consent in writing of the licensee, use energy supplied to him under one method of charging in a manner for which a higher method of charging is in force. (3) In the absence of an agreement to the contrary, a licensee may charge for energy supplied by him to any consumer- (a) by the actual amount of energy so supplied, or ¹[(b) by the connected load in the supply, or] (c) by such other method as may be approved by the Government. (4) Any charges made by a licensee under clause (c) of sub-section (3) may be based upon, and vary in accordance with, any one or more of the following considerations, namely:- (a) the consumer's load factor, or (b) the power factor of his load, or (c) his total consumption of energy during any stated period, or ²[(cc) the maximum demand by the consumer, load sanctioned by the licensee or contracted load, or] (d) the hours at which the supply of energy is required.