Why is my invoice tolerance amount-based not working?

Summary:

My setup for Amount-Based Invoice tolerance is not holding my invoice.

Content (please ensure you mask any confidential information):

I have a PO and Receipt amount of $400 USD.

I matched the invoice with the PO for $418 USD (excl. Tax)

My setup is as follows:

Ordered Percentage - 5 (5%)

Maximum Ordered - N/A

Received Percentage - 5 (5%)

Maximum Received - N/A

Conversion Rate Amount - N/A

Total Amount - 15

I am expecting that my Invoice will be held because I exceeded the Total Amount 15 threshold. I received a warning of "Completing this match will result in an overbill. (AP-810197)". I clicked Ok then proceed on validating. But it did not get held.