If a bank is writing an operating note for one year I don't think it would ever get called unless there where unusual circumstances like fraud or an unknown liability. I realize that banks can call a loan whenever they want to but a small local bank would never do that to their customers for no reason and stay in business. I would not worry at all about an operating loan being called in the middle of the year. I am sure that most customers would not be able to just pay off an operating not during the season or they would not have needed that loan.