Unless your home country embassy still issues a proof of income document you will need proof of 12 months of transfers greater or equal to 65k baht.
If applying for a non-o visa at immigration you would not be able to use the transfer option. They only accept proof of yout income from a embassy. The 800k baht would have to be in the bank on day you apply for the visa,
Then during the last 30 days of the 90 day stay the non-o visa allows you could apply for the one year extension of stay based based upon retirement. They 800k baht will have to be in the bank for 2 months on the day your apply.