Marine Cpl
.577 Tyrannosaur.
Ok. Forget about the mortgage since we want to use semantics. If your credit card or any other bill that didn't have a grace period was due on the 1st and you postmarked it on the 1st by the close of business, they would more than likely charge a late fee. Nowhere in the law does it say there's a grace period or that it has to be postmarked by a date.False positive. Unrelated. Your mortgage doesn't 'expire'. Besides, even with your mortgage it'll be due on the 1st with a grace period typically until the 15th or 16th before incurring late charges.
Just saying for those that don't want to play games with their license.