Pune's super area vs. carpet area — feeling misled on size

₹78 lakh for 900 sqft super area in Anand Nagar, Excellaa project — and this is for a 2BHK. My kids have moved out, so we're downsizing, looking for something low-maintenance near a good hospital. I've noticed a huge difference, sometimes 35-40%, between the super area quoted and the actual carpet area. It's almost like a hidden charge, making the price per usable sqft much higher than it appears. I'm wondering if others found that demanding the exact carpet area breakdown helped in negotiation? Or if there's a trick to calculate the true value per usable sqft in Pune. Don't want to overpay for common spaces. Any advice on how to handle this with builders here?