When a consumer checks out, and hits their back button into your store, and then accidentally checks out two times, two invoice header records are created in your wws_invoice.dbf file. The result of this, is a negative gross profit value in your invoice report. To resolve this, the tech support staff will open your wws_invoice.dbf file and 'delete' the duplicated record. If you download the file, you will see some files 'marked as deleted'.
