If an employee's contribution starts at a single time in the Half-Yearly Return, then their contribution is compulsory for regularity until the end of the half-year return. After completing the return, subsequent months are exempted.
For example, if there is an employee whose salary is $12,000 in the month of December 2010, but in the next month, January 2011, their salary increases to $16,000 due to an increment, then deductions are made only until December 2010 since this marks the end of the return period.
However, if an employee's salary is $12,000 in the month of January 2011, and in the following month, February 2011, their salary increases to $16,000 through an increment, then deductions are made only until June 2011 as this signifies the end of the half-yearly return.
Regards,
Gyandeep