Will get onto the level 60-71 soon.
At the moment I am testing the experience gained without XP gain gear and with it also.
First stage so far in my test... with ninja... you have to kill from 75-80 monsters to gain 1 level total:
I have been testing this without EPs, and solo'ing from level 1- 13 now... and on average... 77 monster kills per level
I need to test this further with feeder classes, as I noticed that when I re-rolled Ninja to Fighter, I still had to kill the same
amount of monsters, thus indicating to me, if you have unlocked any class and roll back to feeder, you still have to kill same
amount... thus even in a group, you will not level up as fast as a normal feeder... Note: still have to test this out further.