@Peter ****************
for retirement extension purposes, it's 800K 2 months before applying, 3 months after applying, and not below 400K the rest of the year.
For marriage extension purposes it's 400K 2 months before applying. That's it. Although there are reports of people in the recent weeks being told by Bangkok Bank specifically that the 400K will be frozen in the account for also 2 months after.
I don't think it's a national thing, and I also question the legality of the bank just freezing your account like that without any wrongdoing from your part.