These numbers are taken from the 'INV' (Stock) application.
This application shows the total value of each goods reception and gives a detailed list over all transactions related to that specific reception, from the origin reception to the picking/shipping of the last item related to this. The INV (Stock) application logs each transaction that happens in the warehouse - what comes in, what leaves, when the price is changed - everything that affects the quantity and value of the stock.
The INV (Stock) application is from November 2020 so the data that is shown in consumed on a part (ART) goes back to this date. If consumed data older than this is needed, this can be extracted using reports.