I understand, but it seems that the heuristic can postpone the order exactly on the first PDS validity start date (second case), but do not consider to anticipate the order "using" a PDS that is valid in a period before the requirement date.
The point is: I have to fulfill a requirement for the future, let say next month, and I have a PDS valid only for this week, why heuristic can not think to create a planning order for today?
Consider that I can not shift the demand or extend the validity of PDS to next month.
I appreciate your patient replies.
Mauro.