Joe, I am ok with the calculation, I just can't figure out why some sales appear on the report and some do not.

Hi I have the same problem please.  The Inventory Sales Report does show all my sales.  But the Inventory Planning report shows only some of my sales.  Example.  Customer 1 buys item A and customer 2 buys item A.  Both show on the Inventory Sales Report, but only 1 show on the inventory planning report.  Thank you.  Ann Richmond