Interesting.
My "US" version of the rom has always worked fine. After testing a 2p game, i set the screen flip dip switch to "on", and it was then in cocktail mode. Unfortunately, no matter what I do after that the game will not go back to upright mode, even when the screen flip says "off".
So, I have no idea how to fix your problem, but rest assured I screwed up my settings trying to figure it out!