Got my letter a few days before I applied ( 200 baht) . It just confirms your balance . Banks have a request form . Bangkok bank did mine whilst I waited .
... they definitely want to see it for the 2 months before when you apply and fir full time of “ under consideration” if you go to Chaeng Wattana ...experience from recent application .
Came back myself a few months ago on a non o.( marriage)
I had to apply in Uk as my visa would have expired whilst still in quarantine .
Uk gave me a 90 day visa . Just before that ran out I applied for my usual year at Chaeng Wattana and that went through without any issues .just collected it on Monday .
Your personal choice . All I believe is that you opt for the 1 year and then they put a date to return stamp in .... that is the date you must return with your passport . There’s no option there . You return , take an updated copy of your bank book for the same day and that’s it .
...personally we’ve always just copied our original Khor certs for the past 7 years , Never knew anything about needing a new one each year from your local ampur .