Hi Keith,
Free license for Service requests is only for self-service module. This means the service request application where user raised new service requests/ incidents and views SR then it is free. Updating the oob Self service application to add few more fields to justify business requirements should not impact licensing. I am not 100% sure about the new token calculation methodologies for duplicated ( cloned) self service application. My expectation is that if you are cloning an OOB self Service application then it should not impact licensing. I would raise an IBM case and clarify whether cloned self service application cause licensing impact.