That is what I've been talking about all along. Simply doubling the range by by filling up a half filled tank is absurd at its best.No change as such except the coded limitations in the FCS have been removed. Modifications will be introduced to bring about increase in range to 600+km.
As of now, we can't program BRAHMOS to fly more then 300 km. The extended range in current form could be attained by changing the flight program coding. Even that is not possible overnight in the deployed systems.
For doubling the range, we would have to overhaul the system in a massive way. I don't understand why people live in a bubble that BRAHMOS is capable of 450 km without any change and the range could be doubled by filling up the fuel tank.