Powershell to unlock IIS config section system.webServer/handlers

UnlockIISHandlers.ps1

$assembly = [System.Reflection.Assembly]::LoadFrom("$env:systemroot\system32\inetsrv\Microsoft.Web.Administration.dll")
$manager = new-object Microsoft.Web.Administration.ServerManager
# load appHost config
$config = $manager.GetApplicationHostConfiguration()

Write-Host "Unlocking system.webServer/handlers"
$section = $config.GetSection('system.webServer/handlers')
$section.OverrideMode = 'Allow'
$manager.CommitChanges()
Write-Host "Unlocked system.webServer/handlers"

This didn't work for me, I am trying to unlock section for an application created under a default web site.
The manual steps are as below

1. Select an application from Default Web Site.
2. From right pane select Configuration Editor under Management.
3. From first drop down at top select system.webServer/handlers and from the next drop down select Applicationhost.Config<>
4. From the most right pane under Section select 'Unlock Section'

I dont get any error after the above powershell is executed but system.webServer/Handlers still shows locked for that particular application available under default web site.

Any help?