Just returned from Chaengwattana (Counter J) after applying for a 60 day extension due to Covid-19. Process was smooth overall but they did ask to see my return flight itinerary back to the USA. If you have a return ticket definitely bring a print out of that. They did also seem to look more closely at my address as compared to last time and they even printed out what appeared to be a TM30. They did grant me 60 days even though my flight leaves before that.