I don't have a good answer for you, since I've never seen this particular information mismatch. I've only got one laptop and a couple of iOS devices. I don't really pay attention to what that screen shows me as being "in the cloud." But here's something that may help. Create a smart playlist with the following criteria:
This will tell you exactly how many songs are in each library. They should match up on both computers.
So the results are:
Desktop Smart Playlist: 3946 Desktop iTunes Match: 3953
Laptop Smart Playlist: 3946 Laptop iTunes Match: 3953
Beatunes on Laptop: 3946
Conclusion: iTunes Match requires some time (12 hours overnight in this instance) to give a stable result on library content. Beatunes had been running on the laptop in concert with iTunes (iTunes Match enabled).
Assertion: iTunes Match has to be hosted in a distributed form to allow for the massive parallel processing to support the user community. The replication of consistent information across the respective servers / datacentres needs time. It is quite possible that the desktop and laptop had affiliated to separate Apple computing resource.
Outcome: Worth not being alarmed by apparent minor variation in iTunes Match results on Song count. For my library 3946 is an accurate count of the number of Songs, 3953 accounts for other items and a few potential songs with iCloud Status other than Matched, Purchased or Uploaded.