Charge due dates are used to calculate late fees.

The Due Day is set on the Late Fee Setup tab of the Property screen.

By default, charges are due on the first of the month.

Assume that the due day is the default, the first of the month.

When you run monthly posting, the charges are due on the first day of the month that you run it for. For example, if you run monthly posting for June on 5/25, the charges are due on 6/1.

If you forget to run monthly posting for June until 6/3, the charges are still due on 6/1 (because 6/1 is the 1st day of the month that you run it for).

Late fees are calculated from the 1st. If your late fee setup has a 5-day grace period, the charges will be considered late on the 6th.

One-time charges are any charges that are not created by monthly posting.

If the due day is the default, the first of the month, one-time charges will be due on the first day of the next month. For example, if you create a charge on 5/25, it is due on 6/1. If you create a charge on 6/2, it is due on 7/1.

Late fees are calculated based on the due date of the charge. If you create a charge on 6/2 and your late fee setup has a 5-day grace period, you might expect a late fee on 6/7, but the charge is not considered due until 7/1, and a late fee won't be charged until 7/6.

If you change the default setting, from the first to another day of the month, the behavior is similar. For example, if the due day is the 10th of the month, the charges created by monthly posting are due on the 10th of the month you run it for. If you run monthly posting for January, the charges are due on 1/10.

One-time charges are due on the 10th of the month -- either the current month, if you create them before the 10th, or the next month, if you create them after the 10th. For example, if you create a one-time charge on 1/5, it is due on 1/10. But if you create a charge on 1/12, it is due on 2/10, not 1/10.