I just played with a Satpros just a couple of days ago (and I gave it away..) But here's what I remember. In the Scan menu, there is a way to bring up a transponder that you want to scan. Arrow down to where it says "Modify" and click on it. That magically got me signal quality on a couple transponders when I was setting up a system on Galaxy 18. The info that was in there all looked correct, but it wasn't until I clicked on "Modify" that it finally showed signal quality.
So, my suggestion is to go into the Scan menu, find that transponder and click on "Modify" to see if that helps.