I sent in a check for a magazine subscription a couple of weeks ago, and I got a notice in the mail over the weekend. I overpaid by six cents. I don't know how, since I looked at the amount about fourteen times before writing the check, just to make sure I got it right.
They are giving me an extra issue to make up for this "inconvenience" to me. Or, they will be happy to issue me a check for the overpaid amount. Uh, I'll take the extra issue, thanks!