APO PPDS is Overplanning

We are not getting desired results out of the PPDS Product Heuristic. We run this interactively in /SAPAPO/RRP3 and in batch jobs on the weekends. Interactively we are running heuristic SAP_PP_002 - Planning of Standard Lots. For the most part this is planning perfectly. Whenever there is demand, PPDS is putting a Planned Order to cover it.

Our problem is that if a Production Order is one day (or even a week) later than the demand we want the system to realize that the demand is covered and that the order is just late. We could use Alerts to determine that it is late. In R3 planning, we would get an exception message. However, in PPDS, the system is creating a Planned Order to cover the demand. This means that we have a Planned Order one day and a Production Order the very next day to cover the same demand! Clearly after MRP this causes us to see more/early demand of components if one of the orders is not deleted.

We have tried to use the Maximum Lateness of a Receipt field in the hueristic to handle this situation. It seems to do EXACTLY what we want... but only for Un-firmed Planned Orders. If there is a Planned Order that is 1 day later than the Demand Requirement and we have the Maximum Lateness of a Receipt set to 5 days, the Planned Order is "reused" so the system does not create another one. But if instead we already have a Production Order, the system always puts in a new Planned Order. I would expect this to work exactly the opposite way... a Production Order can cover the demand even if late but a Planned Order would be moved so it can cover it as needed.

I'm sure others must have configured the APO system to do this since it is closer to how planning works in R3. Can someone please give me some suggestions? Do I need a user exit? Is there standard configuration I just can't find?

Thanks,

Eric