Proficy Change Management licensing is as follows.
Each physical PC that is connected to the PCM server consumes a single PCM client license, regardless of how many actual connections are made from that machine.
Each Terminal Services client that connects to the PCM server will consume one license.
Note: Projects that do not include configuration privileges can be Change Managed. In this situation Change Management:
Can act as a place for safe keeping and deployment.
Adds the ability for password changes, alarm setups, and other runtime configuration information to be managed.
Proficy Change Management technical reference.