Just completed another airspeed calibration flight, results seem much better, it adjusted the airspeed ratio parameter from default of 1.99 down to 1.96, and now airspeed matches groundspeed on the crosswinds every time around.
Weather conditions were much better today, wind was from the southwest steady at 3m/s, I circled constantly for 8 minutes with a constant throttle setting and with the AUTO_CAL enabled. Temp was 80 deg F, and humidity was 70%, I'm located in southern Minnesota, so we get fairly high humidity often.
The only thing I've noticed that's unusual is about every other calibration on power up seems bad, the airspeed will show 4-5m/s with the cover still on the pitot tube. Then if I just reboot, it will typically be in the normal 0-2m/s the next time and will be fine, so not sure if the airspeed calibration on power up needs some tweaking?
Will fly some test flight lines later this week and will let you know how it goes, so far so good!