There is no such case law
Law is well settled by judgment of Bombay High Court in case of Veena Coop Housing Soc that contribution has to be on unit basis and not area basis
Its not that individual flats are being repaired warranting members with lesser area to pay less and members with bigger area to pay more
Its repair of the society building as a whole for which contributions are always on unit basis
Consider this - its not that by taking less contribution from members with lesser area the contractor will apply a differential treatment for repairs than he would for that portion of building which is occupied by members occupying bigger area. The contractor will apply the same uniform treatment for the entire society building. The area of the units is of no relevance.
Please check above judgment