It might not be the case everywhere but 'some' offices are asking to see an updated bank book when you go to pick up the final stamp
( about 30 days after initial application ). So it is 400,000 in the bank for 60 days. Make application and if approved return in around 30 days to get one year stamp and 'maybe' have to show 400,000 still in the bank.
I was asked for it this week in Bangkok, first time it has happened.