All is well that ends well I guess..
I got my remaining 11 months of the extension based on marriage stamped in my passport today in Buengkan immigration. They had warned me not to touch the 400K before today. I had already done that when they told me a week after application, and I then put the money back. I Made sure to have an updated bankbook today showing 400K, even though there had been a dip below for a few days which made me a little nervous. They did not ask for anything other than my passport today, and I had the stamp after a few minutes..
For my father the day also went well.. He was previously rejected because they refused to accept monthly transfers for a marriage extension. He wanted to switch from based on over 50 because the danish embassy stopped issuing the affidavits, and his monthly transfers this year was just shy of 65K. Last year the IO wanted to see monthly transfers along with the affidavit, but a better exchange rate then had him hovering above the 65K.
After talking to the embassy, we found out that they have an alternative to the old affidavit. It is roughly the same actually, but can only be done from verifiable pensions. Such as public/government pensions, and it cost 5 times more to get.
Armed with that new piece of paper he wanted to apply again today for the marriage extension. But as soon as they saw the paper from the embassy, that was all they cared about. It shows monthly pension before tax, which in his case is well above 100K a month when converted to baht with todays rate.
So they didn't care about seeing any kind of bank papers or bank book. Only the paper from the embassy was needed, and they then issued him another years extension based on being over 50.
Very confusing process for him this year, and he even had 400K sourced a month ago to prepare for first a 60 day extension based on visiting family, to get time to season that money for a yearly extension.
But again.. All is well that ends well.
TLDR : Answer Summary
The author shares their experience successfully obtaining a marriage visa extension in Buengkan, Thailand, after ensuring they maintained the required 400,000 THB in their bank account. They also detail their father's journey to secure a marriage extension based on being over 50, highlighting the challenges and changes in requirements from the Danish embassy regarding financial documentation. The process was smoother this year, as both received their extensions without excessive paperwork, despite previous rejections due to different rules.