I don't have a lot of information as I have not tried it myself. I have two customers that have tried to purchase more than 30 items and the purchase did not go through. Both called and told me that they were refused because the total was more than 30 items. They were able to email me a copy of their purchase list before they hit the submit button though. I was not alerted by Auth.net so I believe it has something to do with the cart side of the equation. I can send you whatever you need but I am not sure where to look.