I have finally figured out one reason why my open PO number in the Business status is always off.
An open line on a PO was received yesterday.  The original quantity was for 500 yards @ 54.17 a yard for a total of $27085.00.  The total in the BS for open PO's matched the Open PO listing.  This line was received for 529 yards, and the PO receipt is reflected correctly in the BS.  However there is no corresponding Booking for the extra 29 yards, so the open PO's in the BS are reduced by 1570.93. and now does not match the open PO list.