Board Thread:Game Discussion/@comment-11515381-20130716204849/@comment-11368661-20130716235414

It won't affect your rank directly. It will help out down the line because you'll have an extra chance to attack a boss due to your new reserve cube. My 2 advices would be to keep track of how much damage you do to each boss so you have an idea of what you can finish off. Second is to keep leveling up but keep track of when you are about to level up. This way, you can use up your current battle cubes to zero and then gain an extra three instantly when you level up.