Hello!
That is certainly strange. I checked in my account on several different UPS services and Saturday Delivery appears to be available. Here is a screenshot of the shipping sidebar (keep in mind you have to have the service selected in the Service drop-down for the Other Shipping Options to show the available options):
If you either don't have a service selected yet, or the service selected doesn't support Saturday Delivery, the option won't appear (though, the "Other Shipping Options" section should still be there).
Something else to consider - when you are in the grid view for your orders, you can drag-and-drop these shipping sidebar sections so they appear in any sequence you wish. Maybe the sections are in a different order than what's in the screenshot?
Finally, maybe try clearing your browser cache - sometimes that could clear up some unusual display issues.
If none of that is helpful, I suggest contacting ShipStation Support to have them look into this further.
