Why is there a discrepancy in the number of push sends on my test app?

The discrepancy you're seeing in delivery is likely related to the fact that you are testing in a dev environment. A user will only be qualified for a push notification if they have a true session within Localytics, meaning the app was opened, push notifications were accepted, and the app was then opened again. In the instance of a dev environment, devices are typically constantly being reset which would render the push certificate invalid for that particular device. In addition, if the user accepts push notifications and then never opens the app again, they would never have a session registered with "push enabled."