Job question

[Rabbio]

IIRC, that's not accurate. You get an exp boost for 'sub-classes' once you reach level 50 with a combat class. In other words, first you have to level a combat class up to 50 and then you get that exp boost on the other combat classes.

No, the original method described is correct. So long as another combat class is higher than your current one, you get an xp boost. This works starting at level 10 when you can first switch classes.