You are correct.
As far as I know, in the stock configuration there are
two differences between 'On' and 'Off'. In the 'On' position, you can A) turn on the fog lights and B) leave the high beams on. In the 'Off' position, the fogs won't illuminate and the high-beams will only work in the flash-to-pass mode, i.e., holding the turn signal stalk back activates but won't keep them on when you release.
That's it. No differences in which lights are illuminated, no differences in brightness.
As sptsdn said, this topic comes up a lot and I'd encourage you to do a search as well. FWIW, I like my 9-3 a whole lot better since I had the dealer disable the DRL's

.