I haven't checked, but in general it helps to think of ad settings as a "preference" and not a "rule". We get to tell them what we'd prefer, but not really tell them the "must" use any specific setting.

Because G is going to display whatever they please anyhow.

Maybe just my own opinion, but makes AdSense life easier :)

ken b nailed it when he said Google does whatever they want now (and have for a while). They are constantly overriding our preferred settings - not much you can do.