Upgrading to a 3BHK: the real cost confusion

Visited VSquare's project in Sector 70A last Saturday. Need a bigger 3BHK for the kids, my wife's priority is a good school nearby. Base price for a 3BHK around ₹2.2 Cr sunkar toh theek laga, but then they started adding PLC, IFMS, stamp duty, maintenance advance. Honestly not sure if it's all transparent. Bahut confusion hai, kya ye sab charges add hokar final all-in cost kitna banega? Builders often quote one thing and then it shoots up. Also, construction-linked payment plan lein ya thoda down payment wala? What's smarter for a 3BHK in Gurgaon these days?