[impt] Where does the "Withdrawal Quantity " figure came from?

Question

Hello to all,
I just have an issue with withdrawal quantity.  How is this "withdrawal quantity" field computed in MD63.
Here's my scenario:
I have a material ABC for plant 1234.  I have checked the MRP settings of this material for planning strategy and consumption mode.  The planning strategy used is <b>Z0</b> (which is make-to-stock production), with this, the requirements type for planned independent requirements is <b>LSF</b> and requirement type for the customer requirement is <b>Y41</b>.
Now, the comsumption mode is 1 which is backward.  The Bwd. consumption per. is 99. 
As defined in the documentation (provided by SAP) for Demand Management,
"The consumption period (either forward or backward) is specified in workdays and is valid from the current date. Sales orders,material reservations, dependent requirements then consume the planned independent requirement quantities that lie <b>within the consumption period</b> and after (for forward consumption) or before (for backward consumption) the requirements date."
Now, how do you determine the withdrawal quantity based on these information.  Is the consumption period important?  How do I determine the consumption period?  Where do I start the backward consumption?
Thanks.
Regards,
Patvin

Answer 1

Patvin,
In your case PGI to delivery will be done using movement type 601. You can check this in transaction OMJJ, there will be a small check box activiated for movement type "Reduction of Independent requirements".
Since you have 99 days set a backward consumption, system will first consume PIR which is available on todays date, if not found it will go back descending from today to consume.
Say for example:
PIR:
1000 - 01/08/2007
1500 - 15/08/2007
2000 -  01/09/2007
1000 - 10/09/2007
Now if i do PGI for a quanity of 3500, it will first consume, 1000 - 10/09/2007 then  2000 -  01/09/2007 and finally 500 from 15/08/2007.
Regards,
Prasobh