How to Confirm Transaction Fee

Hello,
I have recently begun experimenting with MarketPress and I have it setup and running in PayPal Sandbox. We will be including the transaction fee so I am using the PayPal Chained Payments with Global Cart turned off. So here are my questions:

1. Because GC is turned off, I'm assuming that each seller will be required to obtain their own API Credentials in order for us to be able to take this transaction fee?

2. I am able to complete transactions via the Sandbox successfully, but how do I confirm that the transaction fee was collected? I have logged into the sandbox account associated with the network admin and it does not show any activity though I am able to successfully able to make purchases through the test user store.

I know an App ID is not required in sandbox mode, but I even tried using the sandbox app id and still no sign of a transaction fee being collected anywhere. Any info appreciated.

Thanks

*UPDATE* Nevermind....I figured it out. It's one of those things that you look at for hours trying to figure out before posting in a support forum and then sure enough, 15 minutes after you post you figure it out. What it was was that I still had PayPal Express Checkout as "All Can Use" in the Network Admin. By turning ALL of them off except PayPal Chained Payments it now works. It also eliminates the individual sellers from having to obtain API Credentials from PayPal which is a huge relief.