What timeout setting of RAS means?

We are using RAS server (BOXI R2 SP3 on windows with IIS) for Crystal report display. I would like to disconnect connections as soon as the report processing is complete. For this when I look into the idle timeout setting on server Tab then it says that its the setting which will wait for "x" mins before closing an idle connection. When I look into Administrator guide then it says that keeping this value too low will result in disconnecting users's request prematurely.

Now I am confused. If this setting says that idle connection will be closed then how come it will close active connections prematurely. Idle connection means its no more in use.

I would like to set this value to very low i.e. 1 min so that resources are freed up as soon as report is displayed and connection is idle.

Thanks,