Explanation: For the purpose of this sub section, (a) the expression 'wages ' does not include overtime wages; (b) the expression 'average wages ' means the daily average of wages for the days an employee actually worked during the thirty days immediately preceding the date of termi nation of service; 734 (c) an employee in an establishment shall be deemed to have been in continuous employment for a period of not less than six months, if he has worked for not less than one hundred and twenty days in that establishment within a period of six months immediately preceding the date of termination of the service of that employee; (d) where the total continuous employment is for a fraction of a year or extends over a fraction of a year in addition to one or more completed years of continuous employment, such fraction, if it is not less than a half year shall be counted as a year of continuous employment in calculating the total number of years for which the gratuity is to be given.