At FlashBox, we always try to offer the most optimized routes and shortest routes possible to our drivers. However, if you're willing to change the order of the deliveries, you can choose to complete routes out of order. You can do so by selecting the next delivery out of order from the map view or the list view on the route summary page.
Keep in mind that the suggested delivery order is used to determine an expected delivery time and is communicated to customers. So it is always best to follow the delivery in the suggested order.