Invoice above service tolerance not put on hold

We have setup service tolerance with 0% tolerance in AP and this tolerance is assigned to supplier site. We created a $100 PO for the supplier with a 2 way Puchase Order match.  Created an invoice for $150 and match to this PO, & changed the PO matching amount to $150 that prompted an overbilled message.  Clicked action button to Validate the invoice, invoice pass validation and not put on hold. This is not what I expected.

I did the same process in another client's instance, the invoice failed validation and was put on hold as expected.

I tried to serch metalink for an answer why an invoice that was above tolerance still get validated without a hold but couldn't find any.