what DRDO Chief said that Brahmos range is 600 km in ' Hi-Hi " trajectory is a technical point ..and that pertains to current versions of Brahmos that we already have ...
But the fact that the Brahmos range can be extended upto 500 km in even in its conventional mode is very important .
this is different from the 600 km range in " Hi -Hi " mode that you talked about .
Extended range of Brahmos which is a very high precision strike weapon is extremely important to take out deep seated high value targets in enemy territory ...
that's why the Long Range Supersonic Cruise Missile project has been tightly wrapped in secrecy ...