I just noticed a bug. Not sure it is from the FedEx plug-in, or paypal express checkout, or OPC.

So if I used the paypal express checkout button to checkout in the shopping cart page, during the shipping method selection (it is the traditional 3-page checkout), I can see both FedEx 2day and 2day saturday delivery. But if I selected 2day saturday delivery, in the next page, it will display the regular fedex 2day, not saturday delivery. The quote is the same as non-saturday delivery option.

There is no such issue under the OPC one-page checkout.