Examples are given below for illustration:
Example 1: The deadline falls on a Thursday. Payments made on Friday, Saturday, or Sunday are not more than 3 days overdue, and therefore incur no late penalty. Payments made on Monday, Tuesday, or Wednesday are more than 3 days overdue, and therefore a 1% late penalty is added (and so on).
Example 2: The deadline falls on a Friday. Payments made on Saturday, Sunday, or Monday are not more than 3 days overdue, and therefore incur no late penalty. Payments made on Tuesday, Wednesday, or Thursday are more than 3 days overdue, and therefore a 1% late penalty is added (and so on).
Example 3: The deadline falls on a Saturday or Sunday (extending the deadline to Monday). Payments made on Tuesday, Wednesday, or Thursday are not more than 3 days overdue, and therefore incur no late penalty. Payments made on Friday, Saturday, or Sunday are more than 3 days overdue, and therefore a 1% late penalty is added (and so on).
Example 4: The deadline is on a holiday (e.g. the holiday is on Wednesday, extending the deadline to Thursday). Payments made on Friday, Saturday, or Sunday are not more than 3 days overdue, and therefore incur no late penalty. Payments made on Monday, Tuesday, or Wednesday are more than 3 days overdue, and therefore a 1% late penalty is added (and so on).