Wsus Script - How to Filter only approved updates

Hello,

I've already done a basic script to get a report of approved updates by queried computer, but in some cases the results are reporting some 'NotApproved' updates

$computername='testcomputer.mydomain.com'

$updatescope = New-Object Microsoft.UpdateServices.Administration.UpdateScope
$updateScope.ApprovedStates = [Microsoft.UpdateServices.Administration.ApprovedStates]::LatestRevisionApproved  # Includes updates whose latest revision is approved.
$updateScope.UpdateApprovalActions = [Microsoft.UpdateServices.Administration.UpdateApprovalActions]::Install

$updatescope.ExcludedInstallationStates=@('NotApplicable','Installed')

$mycomputer=$wsus.GetComputerTargetbyName($computername) 

foreach ($update in $mycomputer.GetUpdateInstallationInfoPerUpdate($updateScope) ) {
        $updateinfo=$update.getupdate()
        [pscustomobject][Ordered]@{
           Status=$update.UpdateInstallationState
           Approval=$update.UpdateApprovalAction
           ArrivalDate=get-date $updateinfo.ArrivalDate -format dd-MMM-yyyy
           Title=$updateinfo.title
        }
      }  

This code produces a short report of pending updates on the majority of my computers, but In some I got results like these

     Status    Approval ArrivalDate Title                                                                                                                              
      ------    -------- ----------- -----                                                                                                                              
NotInstalled NotApproved 08-Aug-2017 Update for Windows Server 2012 R2 (KB4033428)                                                                                      
NotInstalled NotApproved 10-Jan-2018 Microsoft .NET Framework 4.7 for Windows 8.1 and Windows Server 2012 R2 for x64 (KB3186539)                                        
NotInstalled NotApproved 11-Jul-2018 Microsoft .NET Framework 4.7.1 for Windows 8.1 and Windows Server 2012 R2 for x64 (KB4033369)                                      
NotInstalled NotApproved 24-Jul-2018 Update for Windows Server 2012 R2 (KB4339284)                                                                                      
NotInstalled NotApproved 10-Oct-2018 2018-10 Security Only Quality Update for Windows Server 2012 R2 for x64-based Systems (KB4462941)                                   
NotInstalled NotApproved 18-Oct-2018 Update for Windows Server 2012 R2 (KB4462901)

What is the reason that some computers are reporting 'NotApproved' action? Is the following filter the appropriate by my purposes -> [Microsoft.UpdateServices.Administration.UpdateApprovalActions]::Install

Or should I add a second filtering like -> $mycomputer.GetUpdateInstallationInfoPerUpdate($updateScope) | where {$_.UpdateApprovalAction -ne 'NotApproved'}

Best Regards