Gaurs project mein PLC charges kitna reasonable hai?

I'm planning to sell my big house and get a smaller flat in Noida, maybe Sector 36. Kids have moved out toh itna bada ghar bekar hai. Gaurs project dekha tha, but PLC charges samajh nahi aa raha. They're quoting almost 10% extra for floor and location. Is it negotiable, yaa phir normal hai? Also, resale value kitni hogi after 5-7 years? Don't want to lose money, yaar. Anyone faced similar situations? Koi tips?