This breaks down charges for the selected invoice by invoice category. For each category it indicates the:
Invoice Category - One of two criteria considered when allocating payments. All revenue-generating items including Product Catalog items and usage types are assigned an Invoice Category. The order by which Invoice Categories are paid for a customer is determined by category sequence numbers set up in the customer's Accounts Receivable Group. Both Invoice Categories and Accounts Receivable Groups are set up in the Admin Console Data Management application. An Accounts Receivable group is assigned to a customer when the customer account is created.
Charge - Total new charges for the category.
Open Amount - The amount that has not yet been settled (not been paid)