not true. But it's difficult because no bank is now going to open an account for a tourist. Hence they would not qualify since when applying in country you need 800k in Thai bank at time of application, not 2 months prior to extension.
a non-o has no medical or criminal background check or insurance requirement. It can be extended for one year every year. The OA (i think) can be extended by 1yr one time, then you're done and it can't be done again inside Thailand.
They will see your latest tm30 as soon as they bring you up on the computer. I've never brought a tm30 receipt to anything for immigration in hua hin. I just being copy of my lease