This isn't really helpful, but it's an exploit none the less
Whilst i'm leveling my warrior who wields the Whirlwind Axe, i've occasionally used moves the moment i'm about to hit, thus removing that hit. Shortly after, I will experience one number, then another. After experimenting a little more, this is my discovery.
Your about to hit, use a move that will stop you for a brief moment and make you not hit with standard damage [For example, hamstring]. Then, when your preparing for your next hit, you will do one hit, BUT, two damage numerals will come up. This is basically a way of saving damage up though it's not really useful, it can help if you want to do a lot of damage to a mob when they're almost dead.