Sales reports give different totals

You might notice when you run the Detailed Sales Report (or a custom report based on it) that you get a different total for sales than when you run the Detailed Sales with Customer Data Report.  This is because the Detailed Sales does not include sales of items that are not contributing to sales (often Deposit items for a rental) and Voucher/Gift Card sales (those are technically a liability).  The Customer Data report does include these items,w which causes the difference.