it has to be an international transfer, and marked as such in your bankbook. It has to be transferred each and every month to an account in your name only. Where they originate from (company/pension/savings/etc) is of no importance, as long as they are transfered internationally each time.
Everyones situation is different.
There can be many reasons why someone choose the 800K in the bank, or monthly transfers.
Many live on way less than 65K a month, some might not have 65K a month to transfer, others just find it easier to keep the 800K in the bank here.. As they say.. Up to you..
okay 👍 So that means you have either transfered at least 65K each and every month, or are using the combination method. Whatever you are doing, it's at least good that you are aware that it's not just 60K alone each month.
as in, if they deny the application, they just hand you back the papers and passport without doing anything. If they take the application and then not approve it, you will get a new stamp in the passport.
it means if they deny your application it won't be processed at all. If they process it and don't approve it, you will get a 7 day stamp to leave the country.
just remember she has to leave on the same passport she entered on, and that you can only switch the passports by air travel. So leave on the US passport. Enter whatever country you are going to, by air, with the passport that makes sense. Re-enter Thailand, by air, with the Thai passport.
one thing to also keep in mind is the timing. You didn't mention her time of flight. If her flight is by any chance in the early am of the 18th, she could be passing passport control before midnight on the 17th, and there will be no overstay at all, as she would officially have left Thailand at the time she went through passport control.