It lists Shippo orders by order creation date, not delivery date, and defaults to the current week (Monday through Sunday). In the current version this report has no visible date picker at all — its listing in the reports framework is configured without a calendar or a Begin/End control, so the page header shows no date UI. The only way to view a different week is by adding a dates parameter to the page address in the form start - end (using your date format), or asking support for help. Orders must be paid and have a Shippo rate greater than zero to appear; otherwise you see "No Shippo orders found for this date range."