If you book travel, hotels, air, etc. using Expedia using your tablet, laptop or desktop, be sure to double check the rate using your smartphone. For some bookings, Expedia offers a mobile only discount without notifying the desktop/ laptop/ tablet or the smartphone users of such discount.
No real idea why they are doing it, especially without notification, but they are....
The discount does not require using their mobile app, just using a smartphone triggers the discount if available.