The 800k maintained for 3 months is from application date.
For the many guys (including myself) that just keep 800k + in a dedicated bank account, if they ever wish to change banks I suggest to do it in two hits after the 3 month requirement.
So transfer say 400k three months after application and later the other 400k+.
In your shoes I suggest check with immigration with bank book pages printed out for advice.
For some reason immigration can be very fussy on this.