Here is where I am right now...
After trying to rebuild this thing a billion times, all that is working is the coupon code applying the discount.
When I set the session variable to pull up the coupon uses from the Visitors table, it doesn't return any value at all.
If I use the DA update record behavior, nothing happens to the coup_use column in the Visitors table.
So basically, I am back at square one. I was supposed to have this working by tomorrow... >:(