WCF Service starts twice

Question

I have a WCF service configured to use Net named pipe binding. Here is the configuration of the service.

<service name="XX.Impl.Configuration.ConfigurationService" behaviorConfiguration="DefaultServiceBehavior">
    <host>
      <baseAddresses>
        <add baseAddress="net.pipe://localhost/xx/ConfigurationService" />
      </baseAddresses>
    </host>
    <endpoint name="pipeEndPoint" address="" binding="netNamedPipeBinding" behaviorConfiguration="NoDataContextBehavior" bindingConfiguration="pipeBindingConfiguration" contract="ServiceContracts.IConfigurationService" />
    <endpoint name="pipeEndPointMex" address="mex" binding="mexNamedPipeBinding" contract="IMetadataExchange">
    </endpoint>
  </service>

I tried to start the service as part of the Windows Service, the service started successfully. On the same machine, while this running , I have started the same service, same configuration and same address as part of console application. It runs successfully as well.The only difference is windows service runs under Network Service identity while console app runs on my identity.

I can not understand how the service in console app starts while service in windows service is listening. I tried to run another instance of console app that throws the error with a message " there is another endpoint listening ". This makes sense, i can not understand how first instance of console app is running while the windows service has already started the same service and listening. can somebody explain this?