MRP behaviour with fixed dates sales orders

[former_member600242]

Hi,

we have encountered the following behaviour when we fix the date of a sales order in the future and start trying different MRP runs.

STARTING DATA: PD MRP type; no lead times, no time fences, no GR processing times... ; no security stock, strategy 40 (MTS). External procurement from another plant, so stock transfer requitements will get created in the process.

MD04 is empty at the beginning, there are no requierements yet.

1. We generate a sales order with a fixed date on 31.12.2023 for 1 qty. of material A. The sales order appears in the MRP as a -1 -> OK
2. We run the MRP and it generates a PR with the same delivery date 31.12.2023 -> OK
3. The PR gets converted into STO, so now in MD04 we see both the sales order as a -1 and the STO as a +1 on the same date -> OK
4. We create a new sales order, this time with a fixed date on 30.05.2022. MD04 gets updated so we now have -2 from the sales orders and the +1 from the STO. -> OK
5. We run the MRP again, but this time the new PR gets created with the delivery date on the 31.12.2023. Meanwhile SAP has put an exception code 10 in the STO from the step 3, saying that the correct date for the STO is on 30.05.2022. -> Why??

Is this correct?, why is it creating a new requisitionon the furthest date and putting an exception code in the already created STO. Shouldn't it genrate the new requisiton directly on the 30.05.2022 without telling us to change the date of the STO?

Thanks and best regards.

[Caetano]

Please also check this wiki, that explains in detail how rescheduling works:

https://wiki.scn.sap.com/wiki/display/ERPMan/What+is+rescheduling+and+how+does+it+work

[DominikTylczyn · Accepted solution]

Hello fcrespo17

What you see in point 5 is due to MRP rescheduling. MRP first tries to cover requirements with already existing supply elements and if necessary to reschedule them. Only after that if there are any not covered requirements, new procurement proposals are created. Refer to the notes:

• 25388 - MD01, MD02, MD03: Rescheduling proposals: Documentation
• 550302 - FAQ: Rescheduling check

Best regardsDominik Tylczynski

[former_member600242 · Accepted solution]

Hi,

thanks to your response and Caetano's I've been able to understand it clearly.

Thanks and best regards.