No, its required to create a base under Eastern Naval Command.You are wrong about the price:
Let's take the price of the 36 Rafales sold to the IAF as a basis for calculation, i.e. $8 Billion, for the Navy there will be no need to equip bases because the base of these planes is the aircraft carrier! this saves $1.8 Billion. Similarly, the price of the ISEs should not be counted, i.e. another $1.7 billion. This brings us to 4.5 billion for 36 Rafales, or 3.25 billion for 26 aircraft.
Even without that the cumulative package will be around 4.5 billion.