The inventory report used to be a separate menu item per breakdown: by company, by class, by product, by warehouse. They all showed the same data and only the grouping changed.
There is now a single Inventory Report screen and you pick the grouping from the buttons at the top. The report gives value alongside quantity; the value is read from the unit cost written onto the movements, which means the report does not make a cost estimate of its own.
The report on screen and the Excel output run the same query. That removes the “the screen says one thing and Excel says another” problem at the root. The same approach applies to the Stock Statement, the VAT Report and the Profit and Loss Report.