When deploying Application Servers as part of a load-balanced environment, all Application Servers must be configured with the same usage recording and reporting settings within each Application Server's web.config file.
Additionally, if the Application Servers are behind a firewall, they will need to be configured with the ability to make HTTP calls through the firewall to the GCS endpoint. Alternatively, you can place a single Application Server within your network's DMZ, and configure that Application Server to allow for GCS reporting.