Although the Supply and Demand function displays the balance between the supply (available stock on hand and the stock on order), as opposed to demand (requirements) for a part, the function permits you to either include or exclude requirements.
When checked (default), the supply and demand "Detail", and "Graph" tabs will include all requirements that adhere to the criteria selected in the "Requirements" frame.
When unchecked, the "Requirements" frame is disabled, and the supply and demand "Detail", and "Graph" tabs will not include requirements.