This is really interesting. I can't imagine something that would drift THAT far apart with a data rate issue. I do know for a fact that a 25 second WAV file will appear EXACTLY as 25 seconds in LSP. That SAME WAV file converted to MP3 will NOT show up as a 25 second file in LSP. I'll get some odd partial second. Can't remember if longer or shorter, but very, very, VERY odd to say the least. That MP3 loaded in the audio editor WILL show exactly 25 seconds in duration - same in other players.
Again, I just can't imagine the show getting that far out of sync from a difference in data rate. The audio is being played back on the conductor from an independent MP3 board. The rate of the pixelnet data is fixed, so it should not drift. It does seem like the most likely opportunity for drift to be introduced would be during the LSP show creation...
To confirm, you have no issues when playing back from the scheduler??