The issue occurs when “Find trade agreements” is enabled in conjunction with “Use dynamic negative days” within the Master planning parameters form. In the help text for the “Find trade agreements” field, it mentions that assigning a default vendor to an item will override this parameter selection.

In the planning process, the system attempts to determine lead time to expand negative days if “Use dynamic negative days” is enabled. If “Find trade agreements” is also permitted, the system will try to locate a trade agreement with the shortest lead time, regardless of whether a default vendor has been defined for the corresponding item.

The problem occurs because the planned order creation process applies the lead time from item coverage, whereas the dynamic negative days calculation does not. This is resulting in the creation of unnecessary planned orders, rather than pegging against existing planned order transactions.

The solution for using Planning Optimization add-in has a lot of pieces yet ‘to be coming’. Thus not helping the situation. This issue should be fixed.