No, kBpsUp is the currently measured UL rate. The key feature is the little innocent +2.
At startup, there are 0 clients and 0 upload, so two clients can be added. kBpsUp starts increasing, so more and more clients can be added. This goes on until UL reaches the limit. Then the client number stops too (with two more clients, so they get a little less than slot speed if everybody can DL at full speed).