If you bill "multiple payers" there may be a time when you need to create a charge line for a past invoice. You would only need to do this if you find out after the invoice was posted that another payer is going to be paying on that invoice. If that is the case, you will need to add a payer line. Adding a "payer charge line" will create a line item with a $0.00 amount so an adjustment can be applied to it.
