I have the 5D III and the PW Mini TT1 with the PowerMC2 for my Einstein. I tested it this morning, before reading this and noticed some odd behavior. First, I did have banding at 1/200th of a sec. I changed my exposure increments on my 5D III to 1/3 stop, instead of 1/2 stop, and the band went away. I actually shot at 1/250th of a second without it banding. The weirdest thing is that when I shot with 1/250th of a second, the preview image showed as me shooting with 1/200th of a second, and no banding. After a few minutes of testing, I felt comfortable with the results, even with the shutter speed recording incorrectly. I hope the PW Plus III's support the 5D III as I will be purchasing them and selling my Mini and Flex setup. I really don't use the TTL feature as I feel that it is not that reliable, or at least not as reliable as manual.