Philosopher, you just made my day.
Anyway... Wow. Fifth level in a makeup class? Sweet. Does that give you bonuses to Disguise? I mean, a fifth level Rouge... (Just making the standard crack about Rogue/Rouge, let me have my fun.)
In any case... It's been a while since I've looked up favored class rules, but I think that as long as you're within 3 levels of your favored class' level, there's no penalty; otherwise it's 10%. However, it has been a while, so don't take my word for granted.
Myself, I always play human, so I don't have to worry too much about that.