Noida's 'all-in' cost is never actually 'all-in'

Okay I'll be honest — I completely underestimated the final cost of my flat. Just moved into my 3BHK in Sector 151A, an Avexa Buildcon project, last month. Everything seemed clear during booking, but the final all-in cost was significantly higher. Things like PLC, covered parking, and even some unexpected club membership charges kept popping up. It felt like nobody really explains these hidden add-ons beforehand. My main concern now is the super area vs carpet area calculation. They quoted a 1800 sqft super area, but the actual usable carpet area feels so much less. Is this standard practice in Noida? Matlab, what's a reasonable difference between the two? I feel like I ended up paying for a lot of 'unusable' space. Did anyone else face this with their new property? I hope this helps someone else avoid similar surprises.