Apparently I can't renew iTunes Match

Because over the course of the year, my library surpassed their 25000 song limitation. Does anyone know if there's a way to enable Match then de-select a few thousand songs from the cloud?

Another question, although my song library is indeed over 25000 songs, I know that at least 3/4 are available on the iTunes store. My understanding is that Match would store up to 25000 songs that ARE NOT available through iTunes, which means I should still have about 15000 songs remaining before I hit the limit.

Anyone know how to make iTunes recognize music as being available in the store when it had been ripped from CD?