My problem is the Fgoing and Fcoming #'s I am using come up with a RPM that could not be close. Plus the "F" #'s have different values depending on where I sample the speed in WaveosScope.

Here are the Doppler equations.
To get the RPM in the air, we have
f = 2 / (1 / Fgoing + 1 / Fcoming)
and
RPM = f * 60

The question is can I get the Fgoing and Fcoming from the charts below. They are the same chart using a different area to come up with a similar speed