well that information is wrong. Not the 1st time embassies have wrong or outdated info. Seen that from the Thai embassy in Denmark. If you are curious you can check Thai immigration official web site and see what they say about the non o. You will of course find the correct info there.
they are very nice in Udon 😊. For example last year for my extension they were not satisfied with some of the photos - they said just send new ones to us from the Line app 😊