I used 6 data points. Every 500 rpm. I could have used 7 data points and that would have widened the gap between the 2 motors. 7 data points would have used the entire power curve that was measured for each engine. The 7th data point would have put me below the rpm you specified for each engine so it was let out. I could have doubled the data points to 12 and used every 250 rpm but if you look at the shape of the curve you will see that it won't change the average.