Kendriya Vihar resale deal: Kitni negotiation expect karoon?

₹78 lakh for a 3BHK in Kendriya Vihar, GSB Townships ka project, seems decent but it's a resale. I'm in real estate, but buying for myself is a different ballgame. Builders like ATS ya Godrej ke new projects mein discounts milte nahi, max to max ek spot discount for full payment. But secondary market mein kya negotiation scope hota hai? Like, floor-rise premium ka burden kam hota hai kya? Ek deal dekhi hai, 4th floor, owner ko jaldi bechna hai. I'm thinking Jewar effect se prices badhenge, so entry point matters. Does anyone have experience negotiating hard on resale flats in Greater Noida West? Kya 10-15% bhi possible hai if the owner is desperate? Ya broker commissions eat it all up?