Just reporting my experience today at Chaengwattana applying for another Covid-19 extension. I (U.S. Passport) had entered Thailand with an Non-Imm ED visa, which expired in April. After having the visa cancelled, I was on amnesty until Sept 30. I then applied for a Covid extension and was given until Nov 30 with the embassy letter. Today I brought a screenshot of the US embassy website stating they don’t issue letters and copies of all my relevant passport pages as well as a photo. They gave me the covid forms and the TM.7 to fill out and gave me 14 days under consideration, to go back on Dec 1st. They said they will then stamp me until Jan 29th. Booked online so everything was done in about 40 mins. Hope this is helpful for someone!