You can call that method in a loop for each of the VM in the vApp.
Something like this for example
Get-VM-Location (Get-vappDevelopment) |%{
Mount-Tools-VM$_
$DriveLetter=Get-WmiObjectWin32_CDROMDrive-ComputerName$_.Name|
Where-Object {$_.VolumeName-match"VMware Tools"} |Select-Object-ExpandPropertyDrive
$ScriptText="$DriveLetter\setup64.exe /S /v `"/qn REBOOT=R ADDLOCAL=ALL REMOVE=Hgfs,WYSE`""
Invoke-VMScript-VM$_-ScriptText$ScriptText-ScriptTypebat
}