Anonymous participant that's correct. Each entry is for up to 180 days. You can extend one time per entry and get another 180 days, but then you must leave and come back.
There seem to be some folks in this group who have completely missed the basics, so I just thought I'd point it out to be sure.
"been out here nearly full 60 but want to stay longer the dtv is my only option" - just be sure you understand that you need to leave, in order to apply for the DTV. You can't do it in Thailand.
Do you operate under any sort of business structure? Sole trader/proprietor, perhaps?
They're not interested in your income, but under the workcation category, you do need to demonstrate that you're 'doing something useful' outside of Thailand.
Under the umbrella of a registered business, it's probably easier to 'explain', as opposed to just owning income-bearing assets.
If you search, I think you'll find others in a similar situation, including those that 'manage' their investment portfolio remotely.
they'll email you, with the pdf attached. You can always log in and keep an eye on the application, but in my case, it only moved along 1 step after a week, then the next morning I received the email. You can also log in any time afterward, if you need to download the pdf again.