How do I calculate the net cost with tax groups?

How to Calculate the Net Cost 

1. In "Taxes and Adjustments", create a "Sales Tax (Non-Recoverable)".
2. Create a Tax Group. Check Sales Tax for the group.
3. In the"Item" window, locate the product and check "Price Includes Tax Group" and select the tax group PT from the Tax Group dropdown box.
4. The adjusted case cost in the "Items" window will reflect the net cost (adjusted case cost).