Regarding maintenance of Housing Society

These are two different charges, maintenance charge commences after possession of the flat is given. 

Maintenance charges are actually spent during a fixed period that has to be recovered from members.

Development expenses are fixed expenditures like capital expenditure that helps in improving the value of asset and other convenience to all members.

Both are different.

For example, there may be a huge expenditure for deepening a tube well or repairs to entire buildings which costs may be unforeseen or on the high side.  Such sudden, huge expenditure needs to be spent immediately, and hence many societies have such a provision.for unforeseen  & heavy expenditure.

Development is charged one time at the time of improvement of existing infrastructure whereas maintenance is continues process.