I highly doubt those cells were tested one at a time; it was probably from gear ratio, tire diameter, and rpm which would be closer to the actual speed than the displayed speed. There’s some law about never reading low, so nearly 10% gets added to the speedo. There are lots of threads on it if you want to look into it, but that’s the gist.Hmm. I'll have to take a closer look. Is this chart displayed speed or actual?