My Rajkot 3BHK hunt: Super area shocker

Not proud of this but I almost fell for a super area trick when looking at a 3BHK near Kalawad Road. My wife's priority is a good school for the kids, so we're eyeing areas like Mota Mava or University Road. Builders often quote prices based on super area, but the actual carpet area can be 20-30% less. This feels like a major hidden cost, especially when you calculate price per usable sqft. For a place around ₹90L with Maruti Group or Ansal API, how do you even begin negotiating when the base numbers are so inflated? Should I push for a carpet area quote upfront? What about other surprise charges during possession that aren't clear now? Any tips on ensuring transparent pricing or negotiating a better deal in Rajkot? This whole process is confusing.