Some billings are extremely complicated. The billing clerk must assemble many line items of information, as well as account for an array of adjustments and discounts. These invoices will also be reviewed intensively by the customer’s accounts payable staff, especially if the seller has a reputation for issuing incorrect invoices. There is a strong likelihood that these invoices will be rejected due to errors, which means that even more time must then be spent to create a revised invoice.
The possible payment delay associated with invoice errors makes it nearly mandatory to have an experienced person review these more complex invoices before they are sent to the customer. The best reviewer is usually the person in charge of the business relationship with a specific customer, since they are deeply involved in the work being done for the customer. In addition, it may make sense to have an experienced clerk review these invoices for clerical-level errors that might also lead to invoice rejection.
The key issue with proofreading invoices is deciding which invoices to proofread, since the process is time-consuming. Possible options are to require an invoice review for all invoices issued to the more picky customers, or to only require reviews when the number of invoice line items exceeds a certain amount, or when only a certain amount of funding remains available for a customer project.