@Andrew ********
Do a transaction then update the bank book the day you go for the 90 day Non-O visa and it'll show the balance that day
Have the bank print you a 3 month detail transaction report (which is all that's required when you apply for the initial 90 day Non-O) on the spot when you get them to write/print the standard bank letter
At MOST offices that bank letter and the transaction report can be up to 7 days old and still be used