i already talked with schro once about this. haine already said that their attack is the same
i did one test of mobbing to see if they use skills on chase. they barely do (at least skills that bypass shadow armor)
there's only 2 things that increase dmg
monster attack, and your def. considering at one on one their dmg is exactly the same and since their attack is the same.
only one thing left
just like agi flee, vit defense is reduced with mobs, so i think nif mobs are stronger because that formula is different