56. The salary and wages of a worker on which a contribution has been made for a year is equal to the amount obtained by dividing by one-half of the rate of contribution for the year the total of the following amounts:(a) the aggregate of the deductions at source prescribed for the year, minus the amount of any refund of such deductions made under section 78, or which might have been made under such section if no agreement had been entered into under section 79;
(b) the amount which the employer has failed to deduct on account of the employee’s contribution for the year, as he should have done, provided that the employee has given notice thereof to the Minister on or before 30 April in the following year.