I am not 100% sure what your point is?
Do u want a 100% consistent wind indication in your Garmin from the actual metar?
I am not aware of how accurate or detailed the wind is generated, but I reality you wouldnt expect a 100% consistent wind from the metar, thats why the ATC gives you wind directions before TO/Landing. So maybe its just the local variation due to terrain etc. or the way the Garmin is modeled to indicate the wind?