@j.vonstetten 

"...I don't have a calc.avg option..."

The CALC AVG option is showing on your last screenshot.  Click '0.00' next to the any of the items.  That will pull up the Inventory Valuation Detail for that item.  Change the report period to 'All dates'.  That is the report that will show you why QBO is calculating the asset value at 0.00 for all of the items on the report you want - the Inventory Valuation Summary.