the licensee shall so adjust his (charges) for the sale of electricity whether by enhancing or reducing them that his clear profit in any year of account shall not, as far as possible, exceed the amount of reasonable return Provided that such (charges) shalt not be enhanced more than once in any year of account : Provided further that the licensee shall not be deemed to have failed so to adjust his (charges) if the clear profit in any year of account has not exceeded the amount of reasonable return by (twenty) per centum of the amount of reasonable return: Provided further that the licensee shall not enhance the (charges) for the supply of,electricity until after the expiry of a notice in writing of, not less than sixty 844 (2nd column of the page no 844) clear days of his intention to so enhance the (charges) given by him to the State Government and and to the Board Provided further that if the (charges) of supply fixed in pursuance of the recommendations of a rating committee con stituted under sec.