@Pete *********
To get the year extension off a Non O the rules are that you must have the 800k in a bank account two months before applying. It must remain for 3 months after. Your balance cannot fall below 400k for the rest of the year. For the second year extension you can switch to using 12 months of 65k transfers. But you need to have adhered to the rules of the first year extension in order to do so.
It’s possibly best to put the money back up to 800k 2 months prior to your next extension even though you’re going to use the 65k per month option. You technically don’t need to but if there is any reason that the transfer option doesn’t work (late transfer, not over the 65k or whatever) then you have a backup plan to get your next extension and then sort out the issue for the following year.