Deduction u/s 24

Respected Experts, I am in confusion regarding section 24 of IT. If a person is having loan running agnst a commercial property on which he is claiming deduction on intt and now he has taken a loan for the construction of residential prop in F.Y 2014-15. The construction will comlete in F.Y 2015-16. Now for the purpose of calculation of advance tax we have to calculate the deductions. I want to know the procedure of calculation of deduction on intt for this purpose. Should we consider both the properties for this purpose or not. plz guide me.