MRP keeps pushing delivery schedules out, refusing to firm them (ME33L)

Question

I hope someone has seen something like this before and can let us know where to look.  MRP keeps pushing our delivery schedules out even though it is recommending that they be rescheduled in.  What we'd like to happen is for MRP to leave these schedules alone so that they would move inside the time fence and be firmed automatically.  Here is what is happening:
Part X, MRP type P1, firming type 1, MRP group blank.  Planning time fence 05/07/2007, available quantity -20.
Three schedule lines exist for 05/07/2007, two for 10 and another for 30.
MRP will run tonight.  Processing Key = NEUPL, purch req = 2, sched lines = 3, MRP list = 1, planning mode = 2, scheduling = 2
Tomorrow, the planning time fence will be at 05/08/2007 and the three schedule lines will move out to 05/08/2007.  The won't move inside the planning time fence and firm up.  They SHOULD BE 05/07/2006 and firmed!
We originally thought that we may have to create a release with ME84 before these would firm, but it made no difference.  They still won't firm unless someone manually changes the date on each and every schedule line.
Does anyone know what we can change or run to get these schedules to firm up instead of having them pushed out continually?

Answer 1

Hello Randy,
thanks for the update. I didnt remenber this customizing indicator when posting.
Still wondering why planning matters here. I think it should have the same result for all planning modes. Of course planning mode 3 in general should be avoided for performance reasons.
For interested observers I attach the description for this setting in MRP customizing.
Regards, Martin
Indicator: Only Firm Transmitted Schedule Lines
In this step, you can set an indicator which is used to set only those schedule lines that have been transferred to the vendor.
You can firm schedule lines within the planning time fence (in the same way as planned orders or purchase requisitions) according to the master schedule item firming logic. The planning time fence is a number of days that is calculated into the future starting from the current date. Therefore, the last date of the planning time fence changes every day.
In the firming logic, existing schedule lines are also firmed as soon as they move into the planning time fence.
Schedule lines that lie outside the planning time fence and whose quantity is adjusted in the planning run due to a change of the requirements quantity are firmed with the new quantity as soon as the schedule lines move into the planning time fence.
The schedule lines are transferred to the vendor for the amount recorded in the stock/requirements list at the time of the data transfer.
If you only want to firm the schedule lines in the planning time fence that have been checked and transferred to the vendor, you can use the indicator, Only firm transmitted schedule lines. By selecting this indicator, the system only firms the schedule lines that have been sent to the vendor.
For schedule lines whose quantity has changed and which have moved into the planning time fence, the following occurs if this indicator has been set: if the MRP controller/purchaser does not confirm the procurement plan by sending the changed quantities to the vendor, the schedule line quantities that were sent to the vendor in the previous data transfer are firmed within the planning time fence. This guarantees that the system cannot firm any quantities that have not been checked. It also means that the vondor does not receive any messages for unchecked schedule line quantities.
Activities
Define the indicator per MRP group and allocate this MRP group to the materials for which this indicator is to be valid.
Further notes
The message transfer is a purchasing function. You can find it in the purchasing menu, Outline agreement -> Scheduling agreement -> Messages -> Print/transmit.