Ratings changed after trying iMusic

After iMusic was available i tried the service and created an account. To add the iMusic songs to your library an icloud library is necessary so i've tried that but after syncing took to long i disabled it again.

Now i noticed that the ratings of some of my tracks have changed. Tracks that were given a 4 star rating (which a smart playlists uses to determine if the track must be synced to my iPhone) now have the album rating and the rating is colored grey.

What does the grey rating mean and is there a way to select these grey rated tracks with a smart playlist. So i can rate them again.