function dtop {
    $DirectoryDesktop = "$USBDesktopPathServer", "$UserDesktopPath"
    foreach ($Directory in $DirectoryDesktop) {
        Get-ChildItem -Path $Directory -Recurse |
        Where-Object {-not $_.PSIsContainer} |
        Tee-Object -Variable Files |
        Group-Object -Property Extension |
        Select-Object -Property @{
            n = "Directory"
            e = {$Directory}
            },
        @{
          n = "Extension"
                e = { $_.Name -replace '^.' }
                },
            @{
                n = "Size (MB)"
                e={ [math]::Round( ( ( $_.Group | Measure-Object Length -Sum ).Sum / 1MB ), 2 ) }
                },
            Count

    $Files |
        Measure-Object -Sum -Property Length |
        Select-Object -Property @{
                n = 'Extension'
                e = { 'Total' }
                },
            @{
                n = 'Size (MB)'
                e = { [math]::Round( ( $_.Sum / 1MB ), 2 ) }
                },
            Count
    }
}
$tst = dtop
$tst

PS C:UsersMichael Nancarrow> dtop

Directory                                Extension Size (MB) Count
---------                                --------- --------- -----
D:Deployment KitTestDesktop2 txt                        0     1
                                         Total             0     1
D:Deployment KitTestDesktop1 txt                        0    11
                                         Total             0    11