just the correct you slightly Mark remember you’re not coming into Thailand with any Visa at all you were coming into Thailand visa exempt just so you have the terminology correct FYI
vickki has already stated by Brandon your monthly pension deposits don’t really mean anything you need to have 800,000 in the bank two months prior to your filing your first one year extension 
you’re wrong Banks are required to verify customers' identities and the purpose of their financial transactions to prevent them from being used for illicit activities.
maybe in fairytale land, but not in the real world do you have any idea how much illegal money is laundered through foreign banks. if you did, you would understand their concern.