Mark, it’s not a matter of writing anything off: the carb stop is mandatory now. Whether or not someone thinks it helps is moot, you’ve got to use it. The reason Rotax has mandated its use is people who figured out where to limit the slide were much faster, and the people that hadn’t figured it out were struggling/complaining. I’m just relaying what I’ve seen at the first two races at home and what my engine builder saw at the first CanAm race.