Car re-registration and Fitness Certificate cost in delhi

I couldnt find a similar query, hence made this new thread.

We are looking at buying a SX4 at this point. I have decided to trade in my old M800 to the dealer for the exchange bonus.

I have 2-3 queries :

1. What is the cost for re-registration, since the car is nearing the 15 year mark, the dealer said that I will have to pay road tax again (the RC says 1 time road tax paid). He is saying it would cost around 7k including new road tax.

2. What is the cost of registration transfer ?

Also , he says that he will transfer the car only after 1 month to his name or the buyer and not before that. He would give me a delivery receipt, is this normal procedure ?
Thanks