Builder 'all-in cost' quotes in Gurugram are always a lie.

Since we started looking for a 3BHK in Sector 31, the 'all-in cost' figures are wild. Agrante Realty projects look good, but what's the actual total after stamp duty, registration, and PLC? My wife's worried about hidden charges popping up later. Is construction-linked payment smarter for a family budget? We need the true final number.