Maintenance charges for Apartments

I had bought two adjacent apartments in Coimbatore. Tamil Nadu. I made it into one unit with one entrance one electricity connection/ meter. Till date, the maintenance charge was being paid to the builder. The maintenance charge for one flat was Rs.2000 and I was Paying Rs.2000 only for both the flats taken as one unit. Now after four years, the builder will be handing over the the Charge to the RWA(resident welfare Association). My queries are 1. If the RWA makes the maintenance charge based on square feet – should I pay double? 2. If the RWA makes the maintenance charge, fixed charges as before ie.Rs.2000-can I hold on to the same amount of Rs 2000 or should I be pay Rs.4000? 3. Some of my colleagues say that the maintenance charge is for the common amenities and so it should be the same for everyone.Is it so? In the same context, if the project has a mixture of apartments, twin houses and villas- Can the dwellers of the three category, pay the same amount of the maintenance charge.