Negotiating my 3BHK: did I leave money on the table?

₹1.8 Cr for a 3BHK in DLF City Phase 4 was my final deal after months of haggling. Honestly, I thought builders like Mapsko wouldn't budge much, but got 4% off the listed price. My construction-linked plan felt safer, but did I miss out on spot discounts? What did others experience with negotiation, especially on secondary market deals around SPR?