There are a lot of levels to unpack this question fairly so we will touch a few high level points to begin. Firstly it is important to note that our processing time applies to all orders regardless of shipping method (1-2 Business Days) business days are defined as Monday - Friday. While our processing team does their very best to ensure orders with express shipping methods are given the utmost consideration during processing it should not be expected that a priority shipping method provides priority processing. We do not offer any expedited processing of orders.
The next point of this question is the shipping carrier in question. For example unless expressly selected on checkout none of our Express shipping methods include delivery on the weekends. If you order FedEx Next Day Air shipping on Friday but fail to select the "Saturday Delivery" the best case would be you receive that order the following Monday as FedEx defines their express services as "business day transit times".
In the rare case that we dispatch your order with a qualifying Express service that has a delivery guarantee and the carrier misses a set delivery date, we are usually able to work with the carrier to obtain a refund for the shipping or offer a partial credit for the missed service. Please note that most shipping carriers do not refund transit fee's for shipments affected by natural disasters, weather related delays or other delays defined as "acts of god". If you feel your shipment has missed its delivery service guarantee please reach out to us via email at firstname.lastname@example.org. Please take note, there are no delivery guarantees for orders which were fulfilled with Ground or Home delivery services, any delivery dates provided by shipping carriers in regards to these shipments should be considered estimates of the delivery time.