How to add additional invoice cost to item cost without LCM

Summary:

We would like a simple method to update the Item Cost based on additional charges added on the Invoice.

Content (please ensure you mask any confidential information):

Without LCM is there a way to simply incorporate Invoice costs to the Item Cost. We have a simple setup of Creating a PO for item A Qty 100 @ .50.

We do not include Freight or Tax on the PO. When the vendor invoices for the PO they include any Freight and Tax. We are matching to the PO. We add a separate line to the Invoice and capture Freight and Tax as a single line and we use the Prorate across lines checkbox. We would like this additional charge to be included in the Item Cost.