Setting Inheritance and Propagation flags with set-acl and powershell

I am trying to mimic the action of right-clicking on a folder, setting "modify" on a folder, and having the permissions apply to the specific folder and subfolders and files.

I'm mostly there using Powershell, however the inheritance is only being set as "subfolders and files" instead of the whole "this folder, subfolders and files".

Is there some unlisted flag for System.Security.AccessControl.PropagationFlags that will set this properly?

Here's what I'm working with so far.

$Folders = Get-childItem c:\TEMP\
$InheritanceFlag = [System.Security.AccessControl.InheritanceFlags]::ContainerInherit -bor [System.Security.AccessControl.InheritanceFlags]::ObjectInherit
$PropagationFlag = [System.Security.AccessControl.PropagationFlags]::InheritOnly
$objType = [System.Security.AccessControl.AccessControlType]::Allow 

foreach ($TempFolder in $Folders)
{
echo "Loop Iteration"
$Folder = $TempFolder.FullName

$acl = Get-Acl $Folder
$permission = "domain\user","Modify", $InheritanceFlag, $PropagationFlag, $objType
$accessRule = New-Object System.Security.AccessControl.FileSystemAccessRule $permission

$acl.SetAccessRule($accessRule)
Set-Acl $Folder $acl
}