Let's assume, because they used generic numbers also, that some of those numbers are flat rates.
You'd have to make at least 5 bucks for you to not "owe" blizz anything.
They don't want people profiting from micro-transactions.
I see no problem here.
Also the "you owe blizzard a quarter" thing made me think of Mr. Nanny I watched a couple nights ago where Hogan had to pay the taxi driver and the change was "Aw gee, a whole quarter" so the old guy comes up and takes the quarter and says "this ain't charity!".