Are you still getting to the success page? That is the page that sends the email and the only page that would effect it getting sent unless of course you never got to the page at all, which would then be the setting on the confirm page. No matter what it wouldn't be the checkout page.
Perhaps you should consider signing up for a one hour premier support ticket. I can look through it all with you, get it all working and tested and get it all working in under an hour rather than going back and forth the way we have been so far.