Why would a DTV holder ever need a TIN? There's no need for a DTV'er to ever visit immigration. I think you're taking too much notice of the internet fear-mongers, or maybe you're one yourself? Where do you get the 95% figure from? Did the voices tell you that too?
Tax Office has nothing to do with immigration. I won't be crying. I've lived in Thailand for too many years to take notice of internet myths. I have been "tax resident" of Thailand for almost fifteen years and never needed a TIN or to file a tax return. I can't see it changing so I won't be doing anything different from what I've done in the past, as will many expats. If for any reason the Tax Office suddenly decides to change its stance, there will undoubtedly be an "amnesty" as there always is in Thailand. You can be a subservient sheep if you wish, but I'll wait it out!
My advice is don't listen to this guy. He's touting for business. Fact is there are no changes to taxation law which directly affect expats. These laws have always been in place but expats have generally ignored them, and there's no enforcement. Current speculation is based on what "might" happen next year. Like many, I'm just sitting it out to see what happens and I'll then play the DTA card! 👍
Everyone else should also abide by the law. But how many expats pay agents every year, who then pay br*bes to immigration officers to obtain visa extensions? Br*bing government officials is like a cancer in our society - where does it end? And yet for some reason, so many (as you say) think it's ok! 25,000 baht for a 1,900 baht extension. Many expats are happy to pay the 500 baht "fine" for not having a motorcycle licence, or not wearing a helmet when riding, and expats just laugh and say it's "tea money" and that makes everything ok. People are happy to pay 5,000 baht for a f*ke Rolex Watch, and that's all ok. Yes it's a strange place Thailand, but it is what it is. And it's all good. I visit about a dozen national parks every year, so I pay my tax dues in the admission price like all foreigners! 😆
Yes every immigration office has their own rules and nuances. Some seem to go out of their way to make life difficult, which is why the DTV is proving so popular, as for many it can avoid the need to ever visit an immigration office. I can speak only of Chaengwatthana, and I followed the instructions given by another member of this group a while back in how to achieve a non-O without the need for lump sum and without the need to pay an agent. It worked for me