Average cost price is available when you select “Average Costing” in the Settings tab “Inventory” as Method for “Inventory valuation method”:
When set correctly, the average cost price is displayed in the stock valuation report (Menu option Inventory → Analysis & Results → Stock Value / Dutch: Voorraad → Analyse → Voorraadwaarde):
By intent, the average cost price has been created by adding a revaluation to make the difference very clear. Average cost price is based upon all transactions of items in stock:
The average cost price is not available in the REST APIs provided through Invantive SQL, but is in the great old XML API ExactOnlineXML..ItemsEx:
Please remember that it seems that the XML APIs were designed with the business user (finance professional) in mind, whereas the REST APIs have been designed with a developer in mind (which typically is less interested in accounting stuff).
In Invantive Control, you can retrieve Exact Online’s average cost price of an item using the formula I_EOL_ITM_costs_price_value:
Thanks for help on this one from @hjn of Control Info.