The Invoice Summary page shows you a summary of all invoice activities for the current and previous month. You can see a summary of what was invoiced vs. what was collected, totals of all types of adjustments that were made, and so on.
For any given time range, it is possible that the values above will not sum up to $0.00. This is because payments and charges against these invoices may have not necessarily taken place during the same time range.
Examples of this include:
Payments from previous periods can later be allocated to existing outstanding invoices.
Refunds may be applied to payments from outside that period, not linked to either outstanding amounts or invoiced amounts.