15 years of 2BHK, time for a real 3BHK

After 15 years in a 2BHK, I'm finally looking for a 3BHK in Greater Noida for my growing family. Kids ke school admissions bhi paas hain. Okay, I'll say what no one says: builder pricing is a total mystery box. Sab log sirf base price ki baat karte hain. But real all-in cost mein kitna extra lagta hai? I'm looking at India Bricks in Sector 96, and they quote ₹1.2 Cr for a 3BHK. Par phir PLC, parking, stamp duty, registration, aur interiors... yeh sab mila ke kitna jaata hai? Is it really 20-25% more? Aur negotiation kitna possible hai? Brokers bolte hain 'spot discount' mil jaayega, but builder seedha 'fixed price' bol deta hai. Kitna realistically knock off kar sakte hain? 2%? 5%? Super area vs carpet area ka difference bhi ek headache hai. 1500 sqft bolke 1000 sqft carpet area dena, doesn't it feel like a trap? Change my mind.