Key takeaway from your source regarding the Amazon percentage:

​​​​​"Jindel said not to compare Amazon’s performance to FedEx and UPS.

Amazon’s shipping operations are comparable to last-mile delivery for FedEx and UPS, since Amazon products are typically being shipped from somewhere much closer to the customer, Jindel said."

Further, in reference to Amazon's third party ban:

"Jindel said he thinks the move was connected more to FedEx and Amazon's existing tension than it was to FedEx Ground holiday service."