another way to do it :
1 sorcerous
2 master
3 champion
4 fighting
5 amateur
6 debutant
then, with 1050xp, you can do 1x2x3x4x5x8,
and determine class levels by use of the offsets in between two classes :
sorcerous level ====> 0--->1 = 1
master level =======> 1--->2 = 1
champion level =====>...