Chiang Mai Immigration Office 60 day COVID extension update: I just returned after 15 days of "under consideration", getting my actual stamp (with end date 45 days from today). I explicitly asked if I could do another COVID-60-day extension right away, or when I would be able to do so at the earliest (giving the reason that I would be spending March on a small island without an immigration office). They said, they would only accept my new application the week before my current stamp would expire. They also clearly stated, that every day I came early, I would loose, since this COVID-60 day extension would ALWAYS be applied from the day of the application and NOT added to the end date of the former stamp. They admitted though, that other immigration offices (especially in the south) handle this differently. As to a reason why they stated that the big boss in the Chiang Mai office chose to do it that way. This confirms once again what I always assumed: There is not uniform approach to this, and every office can do shit differently. Bottom lime: In Chiang Mai Immigration by the airport, COVID-60 extensions are CURRENTLY only doable shortly before your existing stamp runs out.