Did my extension of stay today at the Nakhon Pathom immigration office. Arrived at 8:15, doors opened at 8:25. Was number 4 in line. After 10 minutes my number was called, handed my Extension of Stay form, Income Statement from Embassy, copy of passport and departure card and 1,900 baht. They took my picture looked at my documents and 10 minutes later at 9 am I was done and left. No problems no extra forms to fill out. The clerk even ask me what was the exchange rate in US dollars.

Cert. of residence too?

Ditto my experience at Maptaput Immigration today. In and out in 45 minutes with new retirement extension and single re-entry permit (for which you don't need to queue up again at Maptaput) stamped in my passport. All I submitted were completed TM7 & TM8 forms, 2,900 THB for the fees, British Embassy income confirmation letter and passport copies (the second set of which I had prepared for the re-entry permit were returned to me). Proof of address was not requested, neither was I asked to sign any new form warning about the consequences of overstaying.