Hi again:
I think we are all talking the same thing.
The evasion still takes place, but in the same hex. This already is done. When fired upon, sometimes you get a message that unit is taking evasive action before the missle hits. Then it gives a percent chance of hit that usually much lower than what it was originally. I've seen Helos do it and I've seen tanks do it (in the wild --- sorry couldn't help it).
I don't read this as a pilot staying stationary, but in the scope of the timeslice all shots are resolved and moving the helo, if it survives, is retained by the player to either continue advancing, change altitude, retreat, etc.
There are actually a couple of units that exhibit the current behavior now that I think of it. Infantry retreats too. So maybe this is a retreat routine for the helo. The difference I think is that in most cases when infantry retreats, it doesn't trigger additional units to fire (I think). When the helo retreats, it can.
So for any particular move, if a helo is detected by 3 SAMs for instance, all 3 get to fire at the helo at the spot it was detected. One could assume that they aren't talking to each other of course and each fire independently or maybe they all communicate and all fire to improve their chance of hit. The missiles move at the speed of sound or greater maybe Mach 2 or 3. You can do the math and come up with time vs distance to see how far a helo might move in the time that it takes a missile to reach its location. My guess is that it is not long. So, that would be the reason for resolving all fire where the helo is. I believe this is the same rationale for all firing in the game. So there is no change as far as this goes. The only change is not letting the computer AI move your helo after it has been shot. Note operative word "after".
Actually this could have some other benefits too! If the helo is damage, instead of retreating, it becomes immobilized on the next turn and is stuck in the landed position, which gives the owning player time to move it to a safe location in the current turn. This also means that you can come across down aircraft in tack. For a campaign, this would mean captured equipment
