AI missile unit loosing formation

AI missile unit loosing formation by taking shot of player's same missile unit is fully unacceptable. i have played more than 10 times in custom battle with 15 arquibuses vs 20 turkish musketeers on VH, sometime less than 10 arquibuses. It turns out to be AI missile unit loosing formation on even once it being shot that i always win such battle.

like MTW1 missile unit, in this version every missile unit except handgunner must stay in tight formation and shoot valley, not overlap the 2 or 3 units line on matchable front in loosing formation unless it taking artillery fire.
i know it's not bug at all, the ceaseless reforming is though, but it's absolutely wrong. it's more fantastic that all AI missile unit stay tight and do valley shot in even such case it takes enemy fire. player can do all such appropriate step but the stupid AI unit isn't set to know that. maybe because it's set the way.