Hi! Currently the system to determine the bracket for Sage World is not perfect. We are constantly looking to improve it. One of the reasons I believe (in my personal opinion) why players are not divided based on Battle Power is because different levels offers players with new talents and skills that are more advantageous to higher levels (gives them more options to choose from and utilize). There is no one perfect solution at the moment but we are looking to improve it over time!

~Jib