A lot of embassy's will send back the passport to the country to be processed by their respect Foreign Affairs. Thai passport holders who renew their passports in London have to wait for passport to be sent to BKK and back again .
Normally it's 183 days in most countries to be classed as a tax resident . Even if Thailand have it in their tax legislation but then ignore it then keep enjoying until they start requesting it
I thought you had to go over the 180 days to become a tax resident . If 180 days you don't become a resident and isn't that the reason they want you to leave for a few days then re-enter on a new 180 day time limit .