I think even guessing is more precise than a calculation would be. If your unit faces a stack of 1000 of unit x and the predictions are 250-500 kills from your attack (criticals not evaluated) then the counterattack can be performed by 750 units, 500 units (and anything between) or what's left if your units crit, 499 or less. Then there's still a normal damage calculation needed for any of the possible remaining enemy units after your attack. From min to max including a possible critical.
I think with guessing the average dmg from both sides you know more than a 100-900 kills possible on counterattack calculation range which would probably appear through such a mod ^^
|