Hyderabad builders' 'fixed price' is a myth

My team in Hyderabad shortlisted a few projects, but I'm still stuck on payment terms. I'm based in Dubai, so site visits are tough. We're looking at Salarpuria Sattva in Keesara for a 3BHK, around ₹1.2 Cr. My main concern is negotiation. Builder bolte hain 'fixed price', but kya Hyderabad market mein actually negotiation chalti hai? Kitna percentage realistically kam ho sakta hai? Also, construction-linked payment plans versus a larger down payment — for an investor, which is the smarter move for cash flow and ROI? And hidden charges? Kya stamp duty, registration ke alawa bhi unexpected costs aate hain possession pe? Need some ground reality checks.