400 km is the theoretical max range, but the open question is whether or not the missile will arrive at the point where it's guidance is turned on with a suitable target in the seekers field of view. The more you push the range of missiles, the more time there is for the INS to allow drift, and the more time there is for the target ships to change location, both of which work against the missile arriving at a point in space where the seeker will find a target with the seeker is illuminated.
Mid course guidance becomes essential, but the survivability of the platform providing that mid course guidance becomes a problem when that platform has to be line of sight with the target. The guidance platform becomes a prime target for the adversary'd defences and against an American carrier strike group, one has to doubt the ability of a mid course guidance platform to survive against the carrier's air wing. It is likely many of these missiles will never find a target simply due to normal guidance errors, ignoring the countermeasures (, jamming, ECM, IRCM, decoys) the Americans would employ. Longer range can work against the attacking missile.