Upgrading in Noida Extension: Pre-launch offers ka sach kya hai?

Noida Extension mein property dekh raha hoon for a 3BHK, upgrading from my 2BHK in Sector 78. Builders like Hawelia Group ya Gaursons ke pre-launch offers kaafi dikh rahe hain. Not sure if pre-launch booking makes sense. Is it actually a good discount, or just marketing? Matlab, kya early-bird pricing ka real benefit hota hai, ya bas wait karna better hai? Also, super area ka funda bilkul clear nahi hota. How do you guys verify the actual carpet area? Lagta hai builders bas numbers inflate karte hain, baad mein problem hoti hai. Kisi ne pre-launch mein book kiya hai kya Jewar side ya Greater Noida West mein? Was the price worth it eventually? And spot discount ka kya scene hai? Kya abhi bhi mil jaate hain ya prices fixed hain? Already have a home loan, so har paisa matters.