As I have said, the car parking area belongs to the society as a common area and this has been confirmed by the Supreme Court. However, in practice, the builder sell the parking spaces to flat buyers. If most or all of them have purchased car parking from builder, they all agree to keep the allotment as per the builder's allotment.
In cases where the society decides to do the allotment itself, it has the right to modify the same.
I do not whether in your society most of the members are following the builder's allotment or it is revised periodically. If it is revised by the society you may request them to provide you a larger area to accommodate the type of car you have. However, for two wheelers, they may make separate arrangement or allow it to be parked near your car if the parking space is bigger.
If most of them are following the builder's allotment, it would be very difficult for the society to provide you with more space, but please request your members and see if you can get a bigger space.
You cannot do anything to the builder now as you have already paid the amount and it may not be worth fighting for as in any case the society members decide on how to allot the parking.
S Jadhav