PENNSYLVANIA TAX COLLECTION LAW

1. Whenever the last day of a period during which payment may be made at a discount or without penalty shall fall on a Saturday or Sunday or on any day made a legal holiday by the laws of this commonwealth or of the United States, Payment shall be considered timely if it is tendered or postmarked by the United States Postal Service on the succeeding secular or business day.

2. The Law makes it clear that a deadline extension only applies to payments at "discount or without penalty" The penalty due date cannot be extended.