At any time after October 15, the county collector shall distrain sufficient goods and chattels belonging to a person who owes taxes upon the person’s personal property, to pay the taxes due upon the personal property and a penalty of twenty-five percent
Since the post office closes at 4:30, and you didn't get your payment postmarked on October 15, your postal mail will be postmarked October 16 and the 10% penalty will apply.