Sector 35: Super area numbers making me doubt

Super area vs carpet area ka game abhi bhi chalta hai kya Faridabad mein? I'm looking at a 3BHK in Sector 35, builder is Goyal Estate Agency. They're quoting 78L for 1500 sqft super area, but carpet area is barely 1000. Matlab, it's like 30% common area! Is this normal? And what about the actual all-in cost? Stamp duty, registration, PLC, parking... kitna extra lag jaata hai on top of this 78L? I work in real estate, but buying for myself is different. Don't want any hidden charges later.