And now we know for sure, thanks again Jon! 
Jon, If you are counting commutator spikes how are you accounting for different pole count motors. A 3 pole and a 5 pole would have about a 60% speed difference unless there is some other factor? G
Since the ERR doesn't have a calibrated speed step like the MTH, I'm not sure that's a big issue. I know there's no allowance for it in the configuration of the CC.
It would be a significant difference in slow speed performance though between the two types, if the spike count was heavily weighted. You would have to know the count I assume for calibration used in the code. So if code was written assuming 5 pole motor, a 3 pole would be significantly faster. Since you would be seeing less spikes per revolution and hence the program would up the voltage pulses thinking the motor was too slow. Similar to a MTH motor with less tach stripes. The program things it is rotating too slowly and increase the PWM to speed it up.
Just an intellectual brain tease, but I would be interested in learning more about it. G
Jon is the guy to ask.
