For now, cheap and cheerful 7cents psf. Fyi, once gst kicks in, services will go up in price. Just imagine those gng now that is charging 20cents psf.

I think its based on built up cause that more likely reflects the number of occupants..example a linked double storey house is likely to have the same number of occupants as a corner unit (cause same interior layout, rooms, bathrooms etc..) however a triple storey house with extra built up/extra bedrooms/bathrooms will more likely hold a bigger family/more occupants..

More occupants - more usage of facilities - more maintenance - hence higher maintenance fees paid..

make sense? there's no one correct formula in this case :-)