clients connecting to windows update and ignoring WSUS ?

Hi

We installed a wsus server and we applied the policy by GPO using registry , but we are monitoring  and  noticed that computers and connecting to IP's from Microsoft, still consuming bandwidth .

We know that the policy is applied since we see the computers are shown in the WSUS and locally the windows update screen show the message that is managed by the system administrator .

I understand ( if I'm right ) that if the computer connects to the server it shouldn't connect to the microsoft servers to search for updates.

This is the .reg we are applying to the computers :

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate] 
"AcceptTrustedPublisherCerts"=dword:00000001 
"ElevateNonAdmins"=dword:00000001 
"TargetGroup"="Corporacion" 
"TargetGroupEnabled"=dword:00000001 
"WUServer"="http://internal-ip"; 
"WUStatusServer"="internal-ip";

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU] 
"AUOptions"=dword:00000004 
"AUPowerManagement"=dword:00000001 
"AutoInstallMinorUpdates"=dword:00000001 
"DetectionFrequency"=dword:0000000a 
"DetectionFrequencyEnabled"=dword:00000001 
"IncludeRecommendedUpdates"=dword:00000001 
"NoAUAsDefaultShutdownOption"=dword:00000001 
"NoAUShutdownOption"=dword:00000001 
"NoAutoRebootWithLoggedOnUsers"=dword:00000001 
"NoAutoUpdate"=dword:00000000 
"RebootRelaunchTimeout"=dword:0000000f 
"RebootRelaunchTimeoutEnabled"=dword:00000001 
"RescheduleWaitTime"=dword:0000000a 
"RescheduleWaitTimeEnabled"=dword:00000001 
"ScheduledInstallDay"=dword:00000000 
"ScheduledInstallTime"=dword:00000009 
"UseWUServer"=dword:00000001