Sooo what about leveling a second class to 60?

[ZDamned]

Because you both have the Armory Bonus because you both have Jobs that are higher level than your 50s.
That's all it takes for the Armory Bonus to activate. Being 60 is meaningless.

I don't know if I'm not explaining this well or something.
The Armory Bonus simply buffs every Job lower than your highest level.
You will both get the Armory bonus at 50, because you both have Jobs that are already higher.
It doesn't matter if his is 59 and yours is 60.

You would only see a difference in xp if you killed something at 59 (when that is your highest) and he killed the same thing.
If you both switch to lower Jobs, you both have the bonus.

I also said in my first explanation that I tested with my 59 paladin as well. SAME EXP. The bonus is a Myth.