It is probably closer to $250/sf. Some spaces are less expensive (living rooms) some a LOT more expensive (bathrooms/kitchens.) A lot depends on finishes…

Economy of scale – building 3 units at the same time, should help… but something don’t get a price break… 3 gas meters, 3 electrical panels and electric meters… Is it going to be common water/sewage? If not – 3 hookups/meters there. All of the utility agencies will have their hands out.