I'm trying to synchronize my music from PC to Android. I synced all my songs the other day by syncing "playlists" and not "music". Why is there a "music" option if syncing playlists also syncs the music within them? And now I've added more songs to my playlists, so I would like to add them to my phone, but when I go to synchronize, it goes through every single song all over again. How do I make it only add the new songs? Is there a way to select the specific songs I want to sync?