I have a spotify premium account. I have a special directory for playlists that I can listen to in offline-modus on my iPod. Parallel I add and remove playlists to and from my special directory on my PC. When I charge the battery of my iPod (approximately every 2 weeks) I also put the iPod online and sync my playlists. The playlists that were downloaded ("local"?) and that I want to keep in my special directory should stay downloaded.
That's were i have a problem: Sometimes it does see my previous playlists as "downloaded". Sometimes it sees all playlists as "not downloaded" (even when they were downloaded) and it starts to download all playlists again.