On p212 of the Corebook (Collectors edition, specifically, but might be the same on the standard edition), it states that
the O-12 Security Council is made up of twelve sitting members: One each from PanOceania, Yu Jing, Haqqislam, the Nomads, and Ariadna. Four O-12 representatives. One seat representing all NonAligned Nations. And an Aspect of ALEPH.
I seem to remember that question being addressed before. Maybe it was on the old forum… I think somebody from Mödiphius replied it was a simple arithmetic mistake, but my memory is not to be trusted.
Cheers! I couldn’t find it on here, and as the Google+ errata tallies have gone, I wasn’t sure which way the error had gone. It being O-12, I guess the number twelve was on the mind!
I am not totally sure, but I think within table top fluff books were also mentioned, that the council possess 12 members. But silly me, I can’t remember.
I also don’t think it is, but when someone wrote the chapter about it he or she might have decided the number of seats based on the 12 of O-12. Or just made the mistake of writing 12 intead of 11 because of the name O-12. I suppose only the author can clarify this…