Question: How come even after choosing to display only owned RT I still see the majority of tracks with N/A in the list?
To answer this question specifically, it is because as can be seen in your screenshot, you haven't selected to only show Styles with RealTracks that are found. I.E. it's possible to have a style (.STY) and not necessarily have all of the RealTracks that it calls for. You can, if you want, load in one of these styles and find the best substitute that you DO have. Right-click on the track | Select RealTracks | Find Best Sub...
If you wanted to get all of the RealTracks, then an UltraPAK upgrade is the best route.