I am a new user of Spotify premium and I don't have an unlimited data plan with my cellular provider. When I make my playlists available offline, do they still use cellular data if I have service? For example, when I use the subway and go underground I know Spotify isn't using my data. However when I return to having service, does spotify then decide to use data again? It is a question I am dying to know the answer to. If anyone can help me out, that would be great.