Deduction from Advance

I have stayed in a rented for around 13 years. Two months ago I was asked to vacate and I did accordingly. During these two months I did not pay rent and told the owner that it can be adjusted from the advance. (No proof for this agreement) I vacated the house and moved to a new house. Now the owner is saying that one month rent deduction is not sufficient and he needs around 3 months. To settle it without spoiling any relation, I had agreed for 1.5 months rent to be deducted. But owner is insisting for 3 months. The reason he says is that the doors, windows etc have become old and those need to be replaced and the house needs to be renovated. So 3 months rent will be deducted. If it is 1.5 months, I will not loose much money. But if it is 3 months, I will have to pay him a good amount. Now that the house is vacated and I am ok to forfeit the remaining money from advance, is there any legal step I have to take? Or can I ignore the ask of paying another 1.5 months rent? (1.5 months rent already covered in advance)