I haven't looked at the Poser 12 manual in a while & it seems a bit muddled on the topic of Queue Manager licenses.  There was actually no limit on the number of render nodes you could setup for Poser 12 and it did not require you to enter a SN.

We added back the requirement for a SN on Queue Manager for Poser 13 to cover the costs of implementing full GPU support on remote render nodes mostly for animators.  Each Poser license comes with 3 seats that you can use for workstations or render nodes (enter that SN into Queue Manager when prompted).  You can add additional seats to an existing Poser license for $99.