This tab displays the customers bill-to information and contacts. They are added to the order when it is first created. Therefore if the customers address and contact info changes while an order exists, the order will no longer match what is in the customer record. This includes customers email addresses that will be used when sending orders and invoices to a customer. There is a button in customer edit that the user can click that will update any open sales orders with the customers new information.
Thanks for your feedback.