BuildMaster user licensing

Is BuildMaster per-user licensing based on concurrent users or user seats?

BuildMaster is licensed to named users who can be managed at any time within the software itself. In our Enterprise Edition we also offer User Classes, which permit only the necessary functions in the BuildMaster software for certain users. For example, your workflow process may require that managers sign-off on a build before it is promoted to the Production environment. The only operation the manager will ever perform in BuildMaster is that approval; therefore, you may purchase an "Approval Only" license at significantly reduced cost for this user.