I teach 4th grade and have my students all day and all year. I have had an issue with some students getting WAY behind the rest of the class as far as level goes. It's impossible for a student 10 levels behind the leader to ever catch up and if unchecked, they will trail the leader by 20 levels by the end of the year. This can be discouraging and make the lower level students stop caring about their level.
My solution to this is to "equalize" everyone at the start of every trimester but allow them to keep all their hard work to earn levels.
I do this by making everyone the same level as the top level student and set all GP to zero. Thus the leader doesn't lose progress they have already made, but everyone is at the same start point at the beginning of the trimester and has a fresh chance to be the class leader in XP.
Let me know what you think!