How are removed items in an order handled?

Overall, removed items for an edited order are included as refunds to ensure that the final total (Total Sales/Total Revenue) matches exactly between your Shopify analytics and Profit Calc.

As if an item is added to the order, it changes the original order total. So to get the final amount included correctly, our app will net out the difference between the newly added item and the removed item (by including the removed item as a refund).