It's vital that your reports show the correct information. QuickBooks Desktop keeps track of various information about expenses so you can see averages as well as totals for product purchases. I can point you in the right direction for assistance with your average cost.
For assistance with an average cost showing incorrectly. I recommend reaching out to the QuickBooks Desktop support team. They'll be able to view your software with you in order to help see the cause of this average cost coming out lower. You can reach out to them using the options provided in the QuickBooks Desktop support policies.
If you have any other questions, feel free to reach out here.