The Over 50 Visa is the 90 day Retirement Visa which will be needed to get bank accounts. When their 800k deposits are seasoned for 2 months they apply for their 12 month Extensions of Stay, not a Visa. No pension is needed at any stage. I assume that the Pakistan Embassy does not provide the income affidavit.
but if your last extension was using the 800k method you have the meet the 800k/400k requirements as well before you get the new extension based on 65k deposits
This could be because you used this method before they changed their "rules" so you are allowed to continue using the pre-change method sometimes referred to as grandfathering.
You failed to meet the requirements of your current extension (i.e. maintain 800k for 3 months after approval then never go below 400k for the rest of the year) so you cannot get a new extension and will have to leave to start again with a new 90 day Non-O.