Confused About Professional Tax Deductions: Should It Be Twice a Month or Just Once?

Hi,

We have developed software related to Payroll, and one of our clients is using our application to pay salaries twice a month — from the 1st to the 15th and the 16th to the 30th or 31st, depending on the month's days. The application deducts Professional Tax twice, meaning it deducts PTAX on the Payslip for the 1st to the 15th and the Payslip for the 16th to the 31st.

I am confused about whether this procedure is correct, or should PTAX be deducted only once a month. I need guidance. Please help.

Thank you.

If a person joins the organization, suppose by the 16th of the month, do we need to calculate professional tax proportionately?