Thanks for the added info. Trying to get a better picture of the AUA…

On the AUA website, all I find with respect to their definition of ratings is this 3 page SOP document, to cover rating and training for both pilots and instructors. This is superficial information, is there more elsewhere? I was expecting something more like USHPA that has 46 pages for its SOP 12-02, just to cover the pilot (not including instructor) ratings alone.

Comparing membership numbers… USHPA  has about 8000 (reference). Roughly, how many does AUA have (not found on their website)?

Aside than less expensive annual dues, and not being USHPA, what are 3 reasons to prefer AUA over USHPA? It was mentioned (here) that “The system is equivalent to USHPA with an even stronger and more complete FAA exemption “. How is it stronger and more complete?