You have answers to your question in the bylaws of the society 

Since the association is registered under Cooperative societies act, the association has to follow the bylaws in this regard which will be specific about the maintenance charges too. 

Supreme Court held that members of a society are liable to pay such dues as determined by a society towards the maintenance and upkeep of flats and common utilities.

Charges for the upkeep of common spaces are often established based on a per-square-foot tariff so that maintenance costs are distributed equally among the flat sizes

Common are is used by all equally, maintenance  should be shared in equal proportion irrespective of size of ownership.

the common area charges and maintenance must be charged EQUALLY and NOT on basis of the land size

charging for common areas based on land size is OUTRIGHT ILLEGAL 

Maintenance charges should be equal to all irrespective of size of villa 

the bye laws adopted by society should contain a provision regarding maintenance charges payable by members 

Dear client, Common Area Maintenance (CAM) charges can be distributed equally among all occupants or based on the proportionate area occupied by each unit.The most common method is to distribute costs proportionally based on each tenant's percentage of the total occupied area.This is known as the tenant's pro rata share.This means that the more space a tenant occupies, the greater their CAM charges obligation. 

The common charges for laying the road should have been borne by the developer at the time of completion of the villa gated community if they are located within the complex.

The association can take a decision in the general body meeting based on the resolution passed by majority members in this regard.

If your association bylaws do not specify the formula specifying the mode for payment of monthly maintenance amount towards maintenance of common areas, then it becomes the duty of the members to arrive at a solution for this through a general or extra meeting of the association.

The society can give a framework or guidelines for the bylaws in common  and certain aspects can be decided by the association themselves especially this being a villa community.

All members should pay equal amounts towards capital expenditure 

AGM cannot pass any resolution regarding maintenance charges 

Please refer to the Act under which the association was registered.

If the Act is silent then equitable proposition is to calculate CAM charges as per area of the property owned which is followed in Apartment Ownership Act in most of the states.

Unable to find any such ruling of Karnataka high court 

if there is no such judgment of Karnataka high court then bombay high court ruling has persuasive value 

It is not fair . All should pay equally 

Yes not only common areas the common maintenance except property tax will be equally divided to all members 

Any judgments even if found to be suitable to your situation will come to your rescue only when you approach court of law seeking relief. 

You have to first of all decide whether the relief sought by you is maintainable as per provisions of law. 

Whatever, you can decide about pursuing the matter legally after discussing with the other members of the association. 

The option before you in the absence of specific provision of law in the approved bylaws in this regard the association can decide about the charging the monthly maintenance amount on the basis of the decision of the majority members by passing a resolution and obtaining approval for the resolution from the registrar concerned. 

If any group of members don't approve the resolution passed by majority then they can plan to approach court of law for relief. 

The calculation of maintenance for common areas is based on common sense 

There is nothing in the act or the rules which say that maintenance for common areas should be calculated such that all contribute equally regardless of the area of their respective units 

Now there is a possibility that the society may call for a general body meeting and put this issue to vote for passing the necessary resolution 

So even if by majority it is resolved that the maintenance for common areas should be charged on basis of area then such a resolution will also be illegal and not binding on those who are affected thereby 

As per law no resolution can be passed for anything which is illegal 

So something which is illegal cannot be made legal by passing a resolution by majority votes. That would be the very anti-thesis of the cooperative movement which is contemplated under the societies act