Stopping the service will temporarily stop the reporting. If the computer is restarted and the service is configured to start automatically, as is the default, the service will begin reporting again.
The Dashboard indicator is a bit confusing. It actually shows the number of computers for which there is data in the database. We will probably change the wording on this.
More importantly, we will soon provide the capability to delete data from a particular workstation. This will reduce the usage count and the number of agents counted toward your license. This functionality will be available on the Report/Agents page.