HOURS LATER SAME DAY UPDATE: got my under consideration stamp until dec 15th and was told I can return for the 60 day stamp as early as dec 9th (earliest possible), up to a few days after 15th. Note: immigration closed for holiday dec 10 & 11
UPDATE ON 60-DAY EXTENSION - I've just been to immigration in Samui (living on Koh Phangan). They are only giving a consideration stamp right now, so you must return no earlier than Dec 15th to get a 60-day stamp that starts from Dec 1st. You can only get the 60-day stamp from the same office that issued the consideration stamp. There's no way around it. I asked to receive both stamps today for an extra cost and they won't do it. Must show proof of registration with current accommodation (I printed out a screenshot received from my guesthouse), several forms (TM7, STM.2, Affidavit form, one photo, copies of all relevant passport pages, 1900B.
TLDR : Answer Summary
The user received an 'under consideration' stamp at the immigration office, valid until December 15. They need to return for the 60-day visa extension starting December 1, but only after December 15, at the same office. Necessary documents include proof of accommodation, the TM7, STM.2, and Affidavit forms, plus a passport photo. Other commenters discuss challenges with proof of residence and the convenience of having originals of required forms ready before visiting the office.
