Invoicing can be seen as complex and sometimes awkward but understanding the process will certainly help. Operators often expect invoices to be “editable” in as much as one can put anything on them or make arbitrary changes. In fact the invoice is simply a collection of transactions.

Transactions are generated during various operations in the system, most often when reconciling carrier invoices. Each shipment typically has many transactions which add up (for each category) to the total chargeable amount. Each transaction can either be un-assigned or assigned to a single invoice. The invoicing system automatically combines transactions for a shipment so that no shipment appears twice on a single invoice. However, a shipment can appear on multiple invoices.

If, for example, you edit the price of a shipment that has already been invoiced then the un-assigned transactions generated by the system (after editing) will represent the difference from the previous total bill. Imagine a shipment that has been invoiced for $50 but you change the price to $40. Internally an un-assigned -$10 transaction has been created. If you preview a new invoice for that customer it will contain this -$10 credit. However, if you cancel the original invoice (unassigning the previous transactions) the new preview will contain simply the updated $40 charge.