The settings area of pro sites reads that you have to enter your ipn url in your pay pal profile when using Express or Pro Checkout
I had this discussion with another cart plugin I was using before joining WPMU.. I had multiple sites with check out pages that required ipn and paypal only has one slot to put an ipn url in..
So if you had two sites that you were selling something on , you had no way of using both ipn url's from the different sites..
The developer of the other cart said that when using pro, it bypasses the ipn of paypal... Is this something specific to that shopping cart or does this work the same way when using Pro with any checkout?
This quote was from the other developer of the other plugin
"PayPal pro does not use IPN at all. "
If this is the case it would clear up confusion to take that verbiage out of the settings area of Pro Sites..