from my correspondence with the consulate in HCMC:
“Regarding the financial statement, kindly print out the transactions within the last 6 months from your bank account and demonstrating a minimum balance of 500,000 THB (it can be from any bank, in any currency), it is should be in one bank account.”
Note the last sentence. Might be a useful data point for you.
this is pretty frustrating considering the rapidly strengthening Thai baht. so you might have qualified a few weeks ago, but now your balance for the last six months wasn’t enough. is there anywhere that shows what exchange rate they use?