I'm on my 4th year retired here using non imm O visa based on retirement. I don't have a pension yet so I use the lump sum of 800k route.
Wednesday 27th I collected my letter from the bank confirming my balance at that date which agreed with my bank book and had been in excess of 800k for more than 3 months.
I arrived at imm at 8.15 and was number 6 in the queue, got called around 9.15 and presented all my documents.
The officer pointed to the last entry/withdrawal in my bank book which was Jan 7th and said I must update it. I explained I have updated it, there are no more transactions, and here's the bank letter dated yesterday verifying that balance. he said I must go to an ATM, withdraw 100 Baht, update my book, make a copy and come back. I again pointed to the bank letter confirming that balance is correct, I don't believe the bank he said.

I didn't have my ATM card with me which I told him was at home in Soi 94, so he said to go do what he said and come back to him, don't queue again. He was polite about it but I've never had this problem before. I thought the whole point of the bank letter was to stop people depositing 800k 3 months in advance, updating their book, and withdrawing it straight away, which I obviously hadn't done as the letter proved plus numerous other transactions in the book over the last 3 months.
So I did what he said at M Village, took it back about 11am and got my visa about 2 mins before 12. ( I did have a puncture on the way back home to get my ATM card so that delayed me a bit).
Again he was polite, also offered to do my 90 date report which was due in about 3 weeks so I accepted that offer, and told me next year to make a withdrawal the same day as the letter which I will and I recommend others do the same just as a precaution.