The Davis is pretty accurate. The differences pretty much come down to siting. The airports tend to have 360° of unobstructed flow to the 10m sited ultrasonic anemometers. The home stations obviously tend to have to deal with buildings and trees and have trouble getting up to the official height. If you have trees around the recommendation is to go even higher than that to get above the tree canopy. Good luck with that.
You can actually read too high in some slanted roof setups if the anemometer is too low since the wind will accelerate as it is forced upward. All of that air flowing in in that column from the peak of the roof to the bottom gets “squeezed” together and it has to speed up the slope…think bernoulli. A good 5ft+ above the peak of the roof should suffice.