Can I switch banks for my visa extension transfers in Thailand, or must I use the same account for 12 months?

I have but not for dtv over the years done it a couple time for my self with marriage visa and for my mom on a retirement visa (moved provicne a few times over the last 15 years). When swapping banks we needed officel statements of both banks showing that the sum amount across accounts was never under the min balance needed. The immigration even directly told us your money can be be across many accounts but just your paper work burden goes up.

If you plan to just swap one time well it will be a 1 off extra papers.

Last time I did this was 2 years ago. So things do chance allways worth just calling up immigration or visiting your local immigration office to confirm that they won't have any issues

(dont forget each immigration officer/office has discretion to reqest extra papers or to cuase you grief they dont normally do in my 15 years happened twice. but worth crossing your ts and dotting your i if you just want to be sure )

Best of luck