My Mukherjee Nagar 3BHK: the real cost shocker

Did anyone else get hit with huge hidden costs after possession? Just got my 3BHK in Mukherjee Nagar from Orchid India Inframart Llp last month. The final bill for interiors, specific PLC, and some utility connection charges was way more than discussed. My initial all-in cost estimate was off by a good ₹10L, seriously impacting my ROI projections. Honestly, things nobody told me! Also, looking back, was a construction-linked payment plan smarter than a larger down payment for managing total acquisition cost? What's your experience with these surprises in Delhi?