DiAPI disconnect delay

I use code below to disconnect my program from sap:

private void Disconnect(){
    oCompany.Disconnect();
    oCompany = null;
}

It works but it takes some time (1-5 minutes) for sap to realise that connection was close. Problem comes when the same user try to lon-on again in any other device. They have to wait until session is really closed by SAP.

I've made a very simple form that connects to SAP and disconnect using that function. If I look at connected clients in SAP, I can see how this software is registered as connected as soon as I connect, but it takes a few minutes to disappear after I disconnect.

Is it possible to force this connection to be closed faster?

* Using sap 9.2, C#, DI API