Yes, it's possible, it's just that SBSettings is finicky. I have noticed that SBSettings doesn't register the moving of icons if you also activate icons at the same time. So, i've had to make them separate steps. For example, I'll activate the 3G toggle, exit SBSettings, wait for/go through the auto-respring, re-open SBSettings and move the toggles (hitting Save in the upper right). Then, all is good and I have my toggles where I wish.
Or, could you be in either the "Dropdown Window" area when you make your changes and the changes don't show because you've got the "iOS 5+ Notification" area activated? Or vice versa? I can't tell you how many times i've made changes to the Dropdown function and am annoyed when the changes don't appear to take affect - only to find out I should have been making the changes to the activated NC area.
Either way - hope some of this reassures. You just got to keep fiddling with it.