I agree with @strawgate … the only way to know for sure it to talk to IBM about it, but I don’t believe Proxy Agents, particularly of computers that are already counted for a license, are counted again against the license count.
That said, I believe the old and discontinued BigFix MDM product made use of proxy agents to manage devices through MDM and those would count against the MDM license count, but they only show up once in the console, not twice.