My family's 3BHK dream hit by surprise charges

My wife and I thought we'd finalised a 3BHK in Naya Bans for our growing family, but ab toh dimag kharab ho gaya hai. SAP Group ke project mein, they're adding huge amounts for floor rise and PLC. Like ₹5L extra for a higher floor and ₹3L for park-facing. Yeh sab hidden costs hain kya? Is this normal for Greater Noida? Kitna negotiation possible hai on these charges? Ya fir ye fixed hote hain? Kids ke school admission ka bhi tension hai.