Scott, there definitely can be problems as you have indicated. If we find problems and identify them to Jos and Norbert they will very quickly fix them.

Things to do with wrong notes have often as not to do with the XG vs GM vs GS standards, e.g., piano playing were it should be the drums, etc. OMB has more features that take care of this whereas in LS you need to make sure that if you are using the GM Wavetable you need to put all drum tracks on 10 and that the drum instruments within the kit conform to the GM standard.