Windows 2008 R2 Server: RDP Sessions remain open until manually closing

I Maintain a Windows 2008 domain with four servers. One is a Windows 2008 R2 64 bit server running RDP with 10 RDP licenses. Here is a description of the situation I'm trying to resolve.

1. Users login and I suspect they just close their session without logging off.
2. I've repeatedly trained users to logoff, but I suspect it does not happen as expected.
3. In Remote Desktop Services Manager, I find user sessions in disconnected status.
4. In RDP-TCP-Properties of RDS-Host Configuration I have the following settings:
   a. Override User Settings - End a disconnected session in 1 hour
   b. Active session limit: 12 hours
   c. Idle session limit: 1 hour
   d. Override User Settings - When session limit is reached or connection is broken, End Session

When I go to Computer Management, Shared Folder, Sessions, I see the following:
1. Many users are listed about 15 times with active sessions
2. It appears there is a session listing for every time they have logged in remotely.
3. The session listings are there until I Click the session and select Close Session or reboot the server.

I have 50 users so this list gets large. About 25 users login at different times remotely with about 4 to 8 at any one time. How do I configure the server to close the sessions after then end (logoff or closed by user).

Is there a command I can schedule to automate this so just the disconnected user sessions get closed without closing actual working RDP sessions?