Sooo what about leveling a second class to 60?

[Allyrion]

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

I just tested it.
I switched to DRG that's at 50 and got an additional 50% xp.
Here is a picture.

As you can see it says lancer experience first at 481 (+115%) experience points.
The second gain was 101 (+60%) on my rogue which is my highest.
The Heat of Battle and full rested experience accounts for the +60% on my rogue.

My 50 lancer gained +115% which would be the 60% from heat and rested, as well as +50% armory bonus.
There's a extra 5% in there for some reason, but the armory bonus is clearly there.