Dell R730 iDRAC virtual console session never timeout

It seems the virtual console session never timeout. From dell guide doc, i found following infor:

iDRAC.VirtualConsole.Timeout (Read or Write)
Description Defines the idle timeout in seconds for the virtual console.
Legal Values Integral values: 60–10800
Default Value 1800

Then i use wsman api to set the timeout to 60 （i think it was for seconds）,  and then i open a virtual console session. It was turned out after the session was being lauched for serveral minutes, the virtual console session is still alive.

Can anyone answer my question?  Thanks in advance!