How to trigger AP approval WF for manually added Freight line to a PO-matched Invoice?

Hi Everyone,

We have a requirement to setup approval workflow using a Spreadsheet for the below use case:

The buyer is creating a PO-matched invoice and adds a non-PO-matched freight line. Now because there is this non-PO matched freight line it is required to trigger a workflow to the Cost Center Manager of the Freight Line distribution line. Any thoughts on how I can configure approval rules to achieve this? We have a rule for PO-matched invoices to get auto-approved.

Thanks in advance.