How to calculate old building cost while buying

1 year ago

I have recently bought a 15+ age property. In the doc, i can see that building is calculated at 1200 per sft for both the floors. Recently i came to know that depreciation rate has to be excluded from that actual building price which did not happen.
2) how to calculate building price? Just because there is a pillar and roof( no enclosed wall), the building value is calculated till there. Due to this first floor building price became 2 lakhs more than 1st floor.
Due to this, i was charged more registration, stamp duty charges and comission fee unnecessarily. The selling party is ready for settlement if any corrections.
My question is, does rectification deed work here? If not what to do? I dont want to lose even more money again in the name of stamp duties and reg charges. Can i get my extra charged stamp charges back? Is there any way i can proceed?
Please let me know if there is any way to rectify my deed and so that i can get back my unnecessary charged taxes from Govt?