1. If Sulu was continuously maneuvering and Nomad was holding same bearing and distance, then there was no way they could've turned to hit it.
2. If Sulu could've turned and Spock confirmed a new bearing then it would indicate a turn to bring forward tubes to bear but that wasn't the case as nothing had changed between them and the target.
3. Since Kirk asked if the location of the target
had changed (and not the bearing to the target
)--which Spock confirmed (IOW, Nomad is not moving but "holding steady")--Sulu maneuvered the ship to fire on that location...