Dear Vanswetha,
At first instance, I was surprised to see the question raised by you regarding how much is to be deducted after the employee took the "Salary advance."
General Practice in the Industry
In the industry, the general practice is that there is a prescribed format which needs to be filled by the employee, duly mentioning how much he/she is going to remit every month or in how many months he is going to clear it. If the terms are accepted, then only the advance is sanctioned.
Secondly, note that at least two sureties will be taken (employees only, and it's the responsibility of the advance taker to get it) when he is applying, to ensure that in any case if this employee leaves.
Approval and Management Discretion
Lastly, make a note that the salary advance is given/approved by the management/MD only, and it's his discretion to agree/disagree on how much to deduct or sometimes to waive off.
In general, these salary advances are not shown in the books of accounts, as the auditors and IT may object. (As per IT rules, there is a need to deduct TDS if paid to any employee from the company's account.) This advance is an internal matter.
So, if the above written confirmation was not taken, kindly ensure the same at least now and get it approved so there is no burden on you/HR.
Do not worry about how much to deduct. They can clear it in a month or 12 months. As you are not going to deduct, the employee has agreed to pay back and management has accepted.
The only thing is you need to ensure the above procedure.
Regards,
Musipatla