I am trying to establish what I need to do to convert my CA$A Grade 2 FIR to FAA equivalent. I havent read deep enough into this post to dare poke my head up with questions yet.
However, when I rang the US Consulate in my city, they directed me to this webpage. It asks questions to try and assist you in determining which type of VISA you will require. Perhaps give it a crack and compare it to what you are being told by flying training provider. Which ever result is the encompassing - go with that. Getting barred from entry will def sink you before you've started. Best of luck.
https://travel.state.gov/content/travel/en.html