Sorry for the delay to answer, I was on vacation. ;D
In my intention the targetshift script has to move the target sligthly every time the choppers fires on it, helping to create a "corridor of fire", thus increasing the overall rockets that must be fired to destroy the target and the area interested by 'em, since the AI proved (as usual) to be very (too much) skilled when engaging a target.
The small shift value (0.03) is a compromise: by increasing this value the AI looses the angagement very often, forcing the choppers to fly around for another passage, with a consequent waste of time and a general delay.
Klavan