Cost of Acquistion in case of flat

No, these costs are not a part of the cost of acquisition, the expenses incurred at the time of purchase are considered as a cost of acquisition, like stamp duty paid, commission paid to the dealer.

The costs mentioned in your query are more towards usage of property than towards flat acquisition. Hence, in my view, they cannot form part of your acquisition cost. As Durgesh ji rightly pointed out, costs which are directly attributable to acquisition of property viz., stamp duty, brokerage, registration charges etc., can be claimed as deduction. Further, Jaipur ITAT in case of Parawati Devi Totlani (ITA No. 120/Jp/2019 dated 28 February 2020) has permitted indexation of interest on loan and thereby allowed it as deduction while computing capital gains