Hi guys im pretty new to the game only started yesterday and i may have ran into some sort of bug, or at least something concerning / confusing.

So my crusader has ATK 373 + 212. Which would equal 585.

And my skullsworn has ATK 473 + 163 which equals 636.

They both make two attacks and are both red type.  Naturally this implies that skullsworn would deal more damage.. this however is far from the case and the reason for my confusion.. tested multiple times, skullsworn hits for an average of roughly 600 each attack, crusader however, attacking the same enemy, hits for over 1000.. 

Can anyone give me an awnser as to why this is the case ?