Hazipur 3BHK: Hidden costs beyond the brochure

What's the actual game with super area vs carpet area in Hazipur projects, especially for a 3BHK upgrade? I'm currently in a 2BHK in Sector 137, thinking of upgrading to a 3BHK or even a small villa in Hazipur. Builders quote a price per sqft for super area, but the usable space often feels so less. I'm trying to figure out if the premium for a 3BHK, say ₹80L-₹1.2Cr, is really justified after factoring in this difference and then unexpected charges like PLC for good views ya parking. Koi experience share kar sakta hai ki kitna difference aata hai in reality? Also, the maintenance charges post-possession are always higher than promised, right? Yaar, already home loan chal raha hai, every hidden cost matters. What are the common hidden charges people only discover after moving in? Hope others can share their insights.