Idling users not being disconnected

[neopozi]

I'm running a licensed copy of v3..

I got 400 registered used in the database. Is it appropriate to to this:

-I need to restart the server for some maintenance reasons while there are 35 users currently online.
-Instead of scrolling all over the user list (of 400 users) in the 'users' tab to find and tick 35 corresponding users and disconnecting them, I tried to switch off all access points so that there will be no data transfer between FS server and the clients.
-I waited for 10 mins (connection idle t/o)... but after refreshing several times, the users are still 'online'... wait for another 5 mins and still the same. I noticed that the duration in the status box was still increasing for every users.
-I stopped FS service successfully and restarted the server.
-after restarted the server, I successfully started FS.
-But then I was surprised to see all the 35 users still 'online' in the status box and the duration was also keep increasing...
-I pressed the 'reset user acc. tble now' and then they are all dissappear.

Any advice is highly appreciated... TQ.