Thanks for reaching out to the Community, amooreCRS.
 

The average cost calculates the sum of the cost of items in your inventory, divided by the number of items. If you have further questions about an assembly's average cost, the best way to find out is by running your Inventory Valuation Summary report. It will show you how QuickBooks got the item's average cost.
 

Here's how it works:

1. In your top menu bar, go to Reports, then Inventory.
2. Choose Inventory Valuation Summary, then set the dates appropriately.
3. Double-click the item you're working with.

I've also included a couple detailed resources about working with average cost which may come in handy moving forward: 

• Understand inventory assets & cost of goods sold tracking
• Common QuickBooks inventory accounting mistakes

Please feel welcome to send a reply if there's any questions. Have a wonderful day!