The "Current Sensor Count" refers to the total number of sensors that have reported in the last 24 hours. To see this value:
Log into the EDR web interface as an admin user
Click Server Dashboard.
Review the "License Information" panel.
The "Online Sensor Count" is the total number of sensors reported in the last 5 minutes.
The "Total Sensor Count" is the sum count of all sensors ever installed - every time a new sensor registers with the cluster, EDR increments this number. If a sensor is uninstalled and later reinstalled, then it counts as 2 for this value. This value has no licensing effect.