Sync Manager

Once the playlists have been analysed and imported, I can show me on the device, if I disconnect it, delete the PC collection and re-alize the same playlist and I return my phone delete all the points of cue, why if the trail is the same?

When I create a playlist on the phone with recordbox the synchronisation but if the load on the reader with rekordbox on the PC tells me that there is no such thing