Forecast delivery schedule is incompatible with the JIT delivery schedule

What causes this issue?

In a scheduling agreement with delivery schedules, for which the
just-in-time (JIT) and forecast delivery schedules are relevant for
materials planning according to the validity of the JIT horizon, the
delivery schedule quantity in the JIT delivery schedule horizon does
not correspond to that in the JIT delivery schedule.
However, the delivery schedule has a quantity in transit that has been
included in the schedule line open quantities but is not included in
the requirements.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

For example:
Forecast dlv. sched Jan 1st JIT dlv. sched Feb 1st (valid to Feb 28)
Cum. delivered qty 100 Cum. delivered qty 100
Cum. received qty 10 Cum. received qty 50
In transit 90 In transit 50
Schedule lines Schedule lines Requirements
Date Qty Open qty Date Qty Open qty
----------------------- ----------------------- ------
Feb 1 20 0 0
Feb 8 20 0 0
Feb 15 20 10 10
Feb 22 20 20 20
Mar 1 100 10 100
Apr 1 100 100 100
The problem arises because on March 1, a requirement for 100 exists
although the open quantity is only 10 when you look at the forecast
delivery schedule only.
However, if both delivery schedules are valid and relevant, the
forecast delivery schedule should also contain a corresponding quantity
for the February schedule lines in the JIT delivery schedule.
At the moment, it is not clear to the system how much the customer
requires for March 1.

System Response

The system thinks that there are differences between the open
quantities and the material planning requirements.

How to fix this error?

You can do one of the following:
Either change the material requirement processing for delivery
schedules in the scheduling agreement.
If you can't change the materials requirements processing, ask your
customer to send you a new forecast delivery schedule that matches the
JIT delivery schedule.
If the customer can't send you a matching delivery schedule, you will
have to adjust the delivery schedule, or enter a new forecast delivery
manually.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.