What i read is that the online application is possible only between 15 days and 7 days before the due date. Then, between 7 days before the due date and 7 days after the due date is only possible to apply in person.
Good question, James. Didn’t decide yet because I still don’t know if I can apply for the Non O inside Thailand having now an extension based on ED visa. If I have to leave Thailand to re-enter with tourist visa then I would consider to apply outside if it’s easier