Deleting from the cloud and then re-adding the tracks can make it worse it seems.
I have an album, Abacab by Genesis. It seemed like a good one to experiment with, I have the CD, I don't really want to listen to it and the name of the album and the first track are certainly unique. This album was ripped in iTunes Plus (256kb VBR 44.1 etc.) from CD.
Originally 3 tracks matched and the other 6 did not. The first track "Abacab" did not match so it can't be a name conflict or anything like that. I'm sure the name is unique. It is also certain that the album is available in iTunes though the album name has a (Remastered)[Bonus Video Version] tacked on the end. This doesn't appear to affect downloading artwork so I doubt it has anything to do with the matching process.
Next I deleted the album from iTunes, including from iCloud. Reran the iTunes Match update. Quit iTunes. Added the album back to iTunes. And finally added the tracks to iCloud again. This time the number of tracks matched was only one. So I went from 3 matching to 1. And it looks like from the status messages, if the tracks were already uploaded, they are not uploaded again even when they've been deleted.
This may be a caching thing so I'm going to wait about 8 hours and try adding the tracks to iCloud again tonight.
Anyone else done this kind of experiment?