Thanks! It does not take it from the original Inventory. When Inventory was received, it was recorded under the following item:

8 oz Black Metal Tin, Inventory Part (Type), Merchandise Sale (Account), Quantity 150

The step that keeps being recommended is to create a sales receipt/invoice, but to use the following item:

8 oz Black Metal (Product Testing), Inventory Part (Type), Product Testing (Account). There is no starting quantity. 

We need to move quantities from the original received inventory - so pull inventory from the 150 quantity and get it into the inventory item for product testing. which is currently at a 0 quantity. 

The recommended steps do not pull inventory from one item to another item in the item list. We also need these steps to properly affect the chart of accounts, i.e. inventory assets (asset account) and product testing (expense account)