I am not sure if this has been resolved yet, but my answer to the MANUAL BASS BUTTON is that its not the 4.0. Its the fact that you have the arabic MODE ON. What that does is it changes features on certain buttons as we all know. On the MANUAL BASS what it does is actualy makes your FILL IN a half measure rather than a whole measure. Could be useful (if you have a bad singer) but I would rather have the MANUAL BASS functionality. Hope this helps.