Another idea was to not 'mess around' and go directly to using a Steamer. The suggestion is to STILL use a Tiger or even a Hack Saw Blade to penetrate the painted layer. You still need to score the paper so the steam can get under there. Once you've done that, you can attack the non-painted layer(s) with the Tiger and DIF.
And lastly, search the Main Forum Page for wallpaper and you'll find LOTS of posts and follow-ups regarding wallpaper removal. (I, for one, have talked EXTENSIVELY about this project.)