My guess is that the commentaries are counted, it is "content" in a sense and if they can get away with doing it then they will.

I've got a few commentaries on 24 that I still need to listen to, although I do generally find them hard to follow because I have seen the episode before, am watching it out of sequence and am trying to follow the episode *and* listen to the commentary at the same time. And then the commentary waffles on about something extremely dull when you would have liked them to talk about a scene the episode has moved onto.

Gareth