Hmmm, everything is fine on my end, and I have those same settings. Have you visited the User CP lately? Not the individual pages, but the actual User CP?
http://www.oddworldforums.net/usercp.php?
To automatically update your timezone, vBulletin takes into account that you'd visit that page at least once every time you visit. If we had the timezone code on every page, it would lag the client side of things. Not too sure if it would affect the server side... More than likely though.
You can go and manually change it though.
Alcar...