how to identify IPV and ERV type Project Expenditures

I am looking at Project Expenditures, and especially at the IPV (Invoice Price Variances) and ERV (Exchange Rate Variances). In the Expenditure Form and also in the tables (PA_EXPENDITURES_ALL and PA_EXPENDITURE_ITEMS_ALL) the source is INVENTORY, even though the actual journal entries are the result of a distribution line on an AP Invoice.

We would like to enhance the information in the Expenditure Form (Supplier Information, Accounting Information - as we have changed this in the SLAM), and I have figured out that the Original Transaction Reference is the INVOICE DISTRIBUTION ID. However I cannot find any other indication to IPV or ERV