) As against its customer, a bank may charge against his account any item which is otherwise properly payable from that account even though the charge creates an overdraft and in such event recover or obtain refund of the amount of the overdraft.
(2) A bank which in good faith makes payment to a holder may charge the indicated account of its customer according to
(a) The original tenor of his altered item; or

(b) The tenor of his completed item, even though the bank knows the item has been completed unless the bank has notice that the completion was improper.