Doddanekkundi pre-launch offers: Is the 'discount' real?

Doddanekkundi keeps coming up for a 2BHK flat. Kids have moved out, so we're selling our big house for something manageable. Keya Homes looks interesting. I'm seeing lots of 'pre-launch offers' from builders. Is buying at pre-launch actually cheaper? Or do they just inflate the initial price to show a discount later? Also, the super area vs carpet area trap... how do you really compare prices per sqft? Honestly not sure if buying early is worth the risk. Any tips on spotting these tricks?