I believe there's a setting when you initialize your library that allows iTunes to manage your library. If this is turned on, when you drag a file into iTunes,

I believe there's a setting when you initialize your library that allows iTunes to manage your library. If this is turned on, when you drag a file into iTunes, Apple copies the file into its own local storage so you have two copies of it. If you delete a file in iTunes it will delete it's local copy. Usually digital collectors will have this turned off if they're using iTunes since they like to organize and name their files elsewhere and they don't want to have two copies of the file. If you manage the library yourself i'm 99% sure you would avoid any funny business, even with an Apple Music subscription. The interplay of Beats, Apple Music, iTunes Match, audiobooks and iTunes was definitely a blunder. In my opinion they should all be separate apps.