Poking around the code inside MarketPress, I see where the payment gateway submits the information but, I may be missing something.
In order to qualify for lower rates, we submit the billing information normally.
Is this being done in MarketPress? Specifically, we submit the billing information and the SHIPTO information so, it's all right there inside of PayPal instead of looking up the name in PayPal and then back over to the website to look up shipping information.
Can we reliably use just the website to get the PayPal transaction information without having to verify on the PayPal side that everything is okay with the payment?