net files /close does not work as expected - powershell

Question

We have many self-written applications which are executed in a network location. Whenever a developer wants to publish a new version of this application, I have to close all opened files on the server where the app is located, by going to:
computer management > Shared Folders > Opened Files
then choose all the files of the application - right click and close.
I want the developers to do that by themselves via PowerShell, so I wrote a Unlock-Files function. This part of the function should close the files, with the net files $id /close call:
$result = Invoke-Command -ComputerName $server -Credential $cred -ArgumentList $workpath, $server {
param($workpath,$server)
$list = New-Object System.Collections.ArrayList
$ErrorActionPreference = "SilentlyContinue"
$adsi = [adsi]"WinNT://./LanmanServer"
$resources = $adsi.psbase.Invoke("resources") | % {
[PSCustomObject] #{
ID = $_.gettype().invokeMember("Name","GetProperty",$null,$_,$null)
Path = $_.gettype().invokeMember("Path","GetProperty",$null,$_,$null)
OpenedBy = $_.gettype().invokeMember("User","GetProperty",$null,$_,$null)
LockCount = $_.gettype().invokeMember("LockCount","GetProperty",$null,$_,$null)
}
}
$resources | ? { $_.Path -like $workpath } | tee -Variable Count | % {
$id = $_.ID
net files $id /close > $null
if ($LASTEXITCODE -eq 0) { $list.add("File successfully unlocked $($_.path)") > $null }
else { $list.add("File not unlocked (maybe still open somewhere): $($_.path)") > $null }
}
if (!( ($count.count) -ge 1 )) { $list.add("No Files to unlock found in $workpath on $server") > $null }
$list
}
I expect net files /close to behave the same way as the manual way I do directly on the server described above, but it doesn't behave like this at all. It sometimes closes the file, sometimes not. But it never closes all the necessary files, so the developer can not publish his application. also, net files almost never finishes with LastExitCode 0, but I can't get my head around why.
Is there a way to force net files to really close all the files?
why would net files behave different than closing the files manually?
Is there a native PowerShell way to do this?
Is there a list of last exit codes, so I can wrap my head around this issue further?
Thank you!