1969 (XXIII of 1969), be paid gratuity equivalent to
[41][thirty days], wages, calculated on the basis
of the [42][wages admissible to him in the last month of service if he is a fixed-rated workman or the
highest pay drawn by him during the last twelve months if he is a piece-rated workman], for every
completed year of service or any part thereof in excess of six months: