Well, I'm always confuzed with that. Same with, Expanded Super Novice, and Kagerou/Oboro. If we look at it from the aspect of one class building on top the previous, they are 2nd classes, but technically they are 3rd classes since they get access to 3rd class max lvl and stats. On iRowiki, these are not 2nd nor 3rd classes. They are simply Expanded classes, like Ninja, GS, and the TK tree (they don't say they are 1st/2nd class).
Lil chaotic
I see =) expanded it is!