For the last few YEARS I have had problems with launch syncing when I launched clips in various scenes. Scene launch worked fine. I have received many good suggestions in this forum that all made the project better but didn't fully fix the problem. I found the answer. The project started out many versions ago and I carried it over each time I upgraded. I recently started the project from scratch in Live 8 and rebuilt the several hundred scenes. Everything works fine.
Maybe this will help someone.