Maintenance model in Aprtment

Dear Sir, Our apartment has changed maintenance model from per square basis to per flat basis. There are total 198 flats in the apartment out of which 6 flats are 1 bhk a. because of this the maintenance of the 1 bhk flat is now became very high. my sale deed has following section written. I own 1Bhk flat are varies from 720 to 1680 sqft in the apartment. ere are the clauses written in my sale deed are ( I Hope weall would have the same/similar) SCHEDULE ‘G’ EXPENSES TO BE BORNE BY THE ‘PURCHASERS’ The PURCHASER shall pay all expenses relating tothe said Flat including internal maintenance and corporation tax relatingthereto Proportionatecost of maintenance, repair, replacement and renewal of all services as andwhen required Proportionatecost of Provision for watch and ward ( security guards) Operators andsweepers and other service and administrative staff Proportionatecost of maintenance of common facilities and amenities including consumable Proportionatecost of periodical cleaning of sump, tanks and overhead water tanks Is it possible for the association to change bylaw and make the rule which not there in my sale deed. Please guide me before I move to court.