Pune 3BHK buyers: What's your real all-in cost experience?

Is it just me, or are builders in Pune really secretive about the *true* all-in cost? We're looking to upgrade to a 3BHK in Ubale Nagar, maybe a Hiranandani project, because kids ka school aur safety wife ki priority hai. Brochures mein base price toh dikhate hain, but then calculations pe aate hain, suddenly so many extra charges pop up. Stamp duty, registration, parking, PLC, floor rise premium... these add up so much! Kitna percentage extra maan ke chalna chahiye over the quoted base price? Kisi ne ₹1.2 Cr ke project mein kitna extra pay kiya hai? Also, negotiation kitna realistic hai Pune mein? Builder bolte hain no negotiation, but I'm sure kuch toh scope hota hoga. Koi tips hai hidden costs avoid karne ke liye, especially those last-minute ones at possession?