Hello,
Have been following this thread for awhile. I would like to add my observations, nothing scientific. First I have had my freak for a couple years at least, hard to recall life before! I live in the Middle East and have a 220V model from what I assume is Hong Kong, serial number ends in HK and has a UK plug. I also use one in Canada which is the lower voltage /wattage model.
I have learned to only use MAX or Fast(Canadian model) when using a pot/pan full of water or oil. For anything else I use the lower settings to avoid wild overshoots, burnt milk etc. This also seems to be pan specific, my cast iron or carbon steel appear to be very excitable, Scanpan, All-Clad and Le Crueset less so. I think I would only use slow or medium with a very thin pan. Deep frying is a joy now!! Sauces, eggs breads etc a breeze. When deep frying or any high temp smoky cooking, I always do this outside. I have never had the unit overheat or shutdown, it's 41C/106F out right now and I would not hesitate using it. Maybe the 220V model has better cooling? Again these just my observations.
CHC, thank you for all your experiments and what you have documented, great resource!!!