Yea, that:
1) 100 (100xp required)
2) 150 (50xp required)
3) 225 (75xp required)
4) 337.5 (112.5xp required)
5) 506.25 (168.75xp required)
Is whats happening I think.
However the total experience has its own value which is displayed to the players, so resetting it would mess that up, I guess i'd have to maby add something that will increase the required xp amount for those 5 levels?
[edit] Oh, khris I missed your question, Required_xp set at 15 But lowered xp given to 10.