Salary tds

Hi everyone,

Can anyone please help me How we can calculate Interest on TDS on salary of an employee means if an employee not submitted his/her investments proof's before Jan then How much needs to deduct from his/her salary ?

Let takes an example

Ram has monthy salary of Rs 35000/- (420000 P.A.)

Transport Allownace : 19200/-

in Income tax declaration he claims 150000/- as investment U/S 80C

so now his salary come below exemption limit of Rs 250800/-

and he is an individual so also takes rebate of Rs 2000/- U/S 87A

so his salar come below exemption limit

But now in jan He said he is not doing any invesment for this year so how much tds and interest  needs to be dedcuted from his salary in last quarter ?

and Can we make ajustment of TDS during the Financial Year with the change in salary due to Increment or due to ansentism?

Please clear me 

Its urgent for me 

Thank in advance