A question about Delegation ( TRUSTED_FOR_DELEGATION & TRUSTED_TO_AUTH_FOR_DELEGATION ) and UserAccountControl

Hello

Can someone please let me with the following question

If I take an AD User Object e.g. UserA (who I set a dummy SPN on just so I can see the 'delegation' tab in ADUC GUI)

If I go to the Delegation tab of the user and set 'Trust this user for delegation to any service (Kerberos only)' aka unconstrained delegation (as far as I am aware, I believe it is also called S4U2Self)

Then when you check the UserAccountControl with a script (I have have tried several) the following it set to True

TRUSTED_FOR_DELEGATION

OK, makes sense so far

if I then set the following in the Delegation tab 'Trust this user for delegation to the specified service only' then I go the section below (which is now available and I have to completed) and set 'Use any authentication protocol' then chose an SPN for a give host on the network.
Then I check the UserAccountControl with a script I now get the following

TRUSTED_TO_AUTH_FOR_DELEGATION

Again the above makes sense (aka constrained delegation which I believe is also known as S4U2SelfProxy)

However this following I do not understand

If I go back to the delegation tab set the following 'Use any authentication protocol' then I go the section below and this time I choose 'Use Kerberos Only'
Then when I run the script, this time the UserAccountControl returns nothing for either TRUSTED_FOR_DELEGATION or TRUSTED_TO_AUTH_FOR_DELEGATION

The last thing above is what I do not understand, i.e. Kerberos constrained delegation is set (and allows Kerberos only so no protocol transition), therefore why is the user AccountControl blank unless I am missing a control in the script

I have the following in the script

{ ($UACValue -bor 0x1000000) -eq $UACValue } {
$flags += "TRUSTED_TO_AUTH_FOR_DELEGATION"
$TRUSTED_TO_AUTH_FOR_DELEGATION_Count++
}

and

{ ($UACValue -bor 0x80000) -eq $UACValue } {
$flags += "TRUSTED_FOR_DELEGATION"
$TRUSTED_FOR_DELEGATION_Count++
}

Am I missing a UACValue ? if so which value please?

Thanks
Charlie