In their previous system (QB) the e-mailing was not automatic, so they brought up the e-mail in outlook adjusted the subject. In this case we have them do a quick print and they are able to do the same. For batch invoices this will not work.
Of course they didn't do the proper testing we directed them to do, so this didn't come up until live operation.
Two lessons from this:
1. When QB is involved remember that they can and will change anything whenever they want, so what may be happening is unpredictable even from user to user.
2. Stand fast on critical tasks, such as user testing, even if it means delaying by a month.