my question ( or complete misunderstanding ) is that stall speed decreases in a turn that exceeds 1G If all calibration is done in wings level stall ( not accelerated ) how is system accurate in a Higher G turn?
AOA is independent of bank angle (or airspeed, or pitch angle, or gross weight, or phase of the moon). An airplane stalls when it exceeds the critical angle of attack. Period. If you stall at a given AOA in level flight, you will stall at that AOA in a turn or pull up.
Since the Dynon system (and other true AOA systems) measure actual angle of attack, they are accurate regardless of airspeed, bank angle, load factor, gross weight, etc. That's why there's been a push lately to install and use them--they're basically always accurate and you don't have to worry about approximations like bank angle, load factor, gross weight, etc.
I can be in an 80 degree bank at 40 kt and not be stalled. I can be wings level at 180kt and stall. All that matters is AOA.