Heuristics creates duplicate planned orders

Hi Gurus,

We have recently changed our phantom BOM's to Manufactured assembly BOM. Currently the heuristics running for the assembly components is the copy of standard lot sizing heuristics and only difference is the resuse mode we are using.We are deleting the unfirmed receipts and recreating again.

Many of the time for the assembly components have the order reservations in the past so when heuristics tries to cover the past demands it creates all all the new planned orders on the current date.Our production planners don't want the planned orders number should change in the next planning run.So to avoid deletion of existing planned order they "Date fix" the planned orders.We are fixing the orders on  this horizon [D(-10) - > D2 ].Now when the planners are running the heuristics , they see that firmed orders are untouched but they see that there are some duplicate orders created.After analyzing i found  that there was no need to creating new planned orders.All the demands in future was covered as per lot per lot strategy and the demands in past were covered by the firmed orders.

I have tested the scenario in simulation version.Please suggest what I can do to avoid creating unneeded orders.

BR

Debasis Nanda