@Martin **********
right, that is exactly what I am saying 🙂
You can go from a 30 day visa exempt entry OR a 60 day tourist visa entry to an in country Non-O visa but you can't come IN on a Non-Immigrant Type visa (no matter the category OA, ED, B, etc) and switch to a different type of one in country <- meaning you can't come in on an OA and switch to an O