Carpet area numbers: the real shocker for families

Super area vs carpet area ka difference Greater Noida mein sabse bada jhol hai, lagta hai mujhe. I'm looking for a 3BHK for my growing family, especially near Sector 150 ya Kakrola. L&T Realty jaise builders ka sales team carpet area theek se batata hi nahi. Meri wife ko kids ke liye proper space chahiye. Kitna percentage difference usually hota hai? Should I insist on seeing the exact carpet area in the agreement? Ya sab builders ka yahi scene hai? Kya extra cost lagti hai agar carpet area zyada ho?