Currently ShipStation does not include or display the Deliver By Date for Amazon orders. This is a critical piece of information. The ship by is given but that does not help the shipper to select the service to use. The requested shipping service is given but in many cases if you receive an order on Thursday for example at 2pm vs 10pm the requested service will be the same but the shipper may need to select Saturday delivery on the 10pm order and not the 2pm order.
So really what matters is WHEN the customer has to get the items by. That is what should dictate what shipping service is used.
So please add that data field into the feed and display it on orders as it will be helpful.