Ghaziabad 3BHK: The real cost beyond brochure price

What's the *real* all-in cost for a 3BHK in Ghaziabad? Upgrading from my 2BHK in Surya Nagar, maybe Indirapuram, budget ₹90L. Builders like Gaurs quote super area; carpet area mein kitna difference aata hai? Besides stamp duty, do PLC, parking, OC *really* add a huge chunk at possession? Already have a home loan. How to calculate final cost beforehand?