@Marco *******
Thanks for the update ... I had my marriage visa renewed in Sept, and I just use a normal bank account, but I also use an Agent (costs about 7,000 baht total) and they gather up my bank statement and deal with immigration, so that may be the difference.
That said I do not let the account go below 40,000 Baht ... maybe until I will start drawing a 'provable/certified' pension and convert to a retirement visa I'll make sure not to rock the boat (I was considering to dip into the 40K and refill shortly after by withdrawing private retirement funds, but I guess I'll just wait for the withdrawal of the funds the transfer to Thailand of the cash instead to save myself some potential questions and issues!?!?