I simply think it is wrong. Or, if not, then the game is really deep!

Why? You can grab a unit of Horse Archers, makes another Archers unit fire at it. By simply, running with the Horse Archers a certain direction when the Archers release their volley, you will evade most of their arrows (You won't see any arrows heat seeking your folks). And, when as soon as the second volley is released, you run the opposite way, you will evade most if not all of the arrows again.. Explain that!

(If what you say is proven true, the simple answer would be that the game's engine calculations are deep. Which contradicts what a lot of vets say about it)