(1) The rate at which a gratuity may be granted under the said section 2 shall be whichever is the higher of the following rates:—
(a) for each year of service as a civil servant, one month's salary and emoluments; or
(b)
(i) for each year of full-time service, up to five years, one week's salary and emoluments,
(ii) for each year of full-time service in excess of five years and up to ten years, two weeks' salary and emoluments, and
(iii) for each year of full-time service in excess of ten years, four weeks' salary and emoluments:
Provided that the total amount of the gratuity shall not exceed one year's salary and emoluments.
(2) For the purposes of this Rule a person's salary and emoluments in respect of any period shall be calculated by reference to the actual rate of his salary at the time when his employment is terminated and the average annual amount of his pensionable emoluments during the last three years of his service, unless he has during such last three years served in more than one class, in which case they shall be calculated by reference to the average annual amount of his salary and pensionable emoluments during the last three years of his service.