What Ghaziabad builders hide on pricing

Visited a couple projects in Chipiyana Buzurg last week, including Parakh Infrastructure. Builders quote ₹65L for a 2BHK, but what's the real negotiation headroom? New projects often have inflated quotes, I've seen this. Is a 5-7% discount realistic on new units, or are secondary market deals in Vaishali better for actual negotiation? Also, with current rates, is a construction-linked plan smarter than full down payment for an investor? Need that ROI.