I use Chonburi immigration also and there is no need for an embassy letter from my home country (USA) However, I have heard rumors that some embassies still provide income certification letters. I don't know how true this is.
about 5 years ago several embassies stopped doing letters (including mine.) I have always utilized the 800K deposit because of convenience and I'll probably just keep doing it for that very reason.
I was under the impression that the non O (acquired in country) was basically the same as the non OA (acquired in your home country) and that the Non O was just a synonym for the 12 month extension of stay. This shite is confusing AF! Thank you very much for the clarification.
I thought the non O (which is acquired in country) and the 12 month extension of stay were essentially the same thing? Are they not? What is the difference?
Your other option is to pay a visa service if you meet neither of the criteria I listed above but it will most likely cost you in excess of $1,000 USD. I hear Key Visa in South Pattaya has one of the lower fees for this service in Pattaya. Good luck!