I've seen it take some time to recognize the files were removed. Is this local space or SAN/Network Attached?
I agree that it seems like a lot of extra space that isn't needed. The other thing to do would be to migrate the VM to a different datastore and switch it to THIN provisioning so the VMDKs are only as large as the space being used. Again, this is if you have shared storage. If you only have local storage, you won't be able to migrate.