The different apps are sold separately.

The android app (Google play store) and the iOS app (iPad, iPhone from the iTunes store) as well as the Mac app are entirely different apps, with separate extensive development. They are sold separately and are not interchangeable between platforms.
I use both iPad and android and have gladly purchased both. Truly a bargain for what they do!
They are all compatible in that I can easily transfer charts and playlists between them.

)BOB