Hello,

Well this point is not well polished. In fact most of the information you need are present in the res.bank object related to res.partner.bank.

My opinion is that the res.bank model was desing as an auto completion utils for the res.partner.bank model. But in the code there is still places where the res.bank data are directly used.

If you can retrieve all informations from res.bank object it's nice, else I would suggest you to customize at least res.bank but ideally res.partner.bank that use res.bank as an auto completion tool and extends the on change.