The super area vs carpet area trap nobody tells you about

Is it just me, or is the super area calculation in Sohna getting crazier? I'm currently in a 2BHK in Gurugram and thinking of upgrading to a 3BHK or a villa in Sohna, maybe around Sector 26A. Adani M2k Projects Llp ke kuch options dekhe hain. Yaar, brochure mein 1800 sqft dikhate hain, but jab carpet area poochho toh hardly 1200 sqft milta hai. That's almost 30-35% difference! This makes the per sqft price look so misleading. Is this normal practice in Sohna? How much actual usable space can one expect? Aur kya ispe negotiation possible hai, ya builder bol dete hain 'fixed'? It's like paying for air, especially when you have a home loan already. Is the price jump for a 3BHK worth it when so much area is just 'super'?