Hi Jeffrey,
It appears to me from your explanation that there is something incorrectly setup with your MRP parameters.If I correctly understand the process that you described, here is what I would expect should be happening.
1.  A Forecast is created in MPS/MRP from the Customer's EDI transmission. It appears from what you said that the Start Date and the End Date of the Forecast are the same value which is the Date on which the Customer wants you to ship the Order from your Plant.
2.  When MPS/MRP runs, I would expect that a Planned Order for the Finished Good Item will be created for the Forecast.  The Due Date of the Planned Order will be the Need Date of the Forecast which is the Start Date of the Forecast.  In this way, MRP is planning for you to have the manufacturing process complete by the Ship Date which is the Start Date of the Forecast.
3.  For this F.G. Planned Order, MRP will calculate the Release Date of the Planned Order using the Lead Time that is defined for the F.G. Item Number.  It will subtract these Days from the Due Date in order to determine the Release Date for the Planned Order.  So, if the Lead Time is 2 weeks, then the Planned Order Release Date will be 2 weeks before the Due Date.  This Release Date is when the S.O. that will be created must start in order for the F.G. Item to be completed by the Due Date.
4.  For all of the 1st Level BOM Components of the F.G., MRP will set their Need Dates to be the Day before the F.G. Release Date.  In this way, MRP will be planning Demands for the Components to be in-house before the F.G. is to be started.  This Need Date will be the Due Date for the Components.  Then, MRP will use each Component's Lead Time in order to determine its Release Date.
5.  If any of the 1st Level BOM Components are themselves manufactured, then MRP will perform the same process to determine the Release Date/Due Date for the next lower Level BOM Components.  This process continues through all BOM Levels.

6.  With the process described above, all of the Item Numbers from F.G. Item down through all Components will have the correct Planning Release/Due Dates.  So, if you execute to these Dates, you should be able to successfully complete the F.G. by the Ship Date. 

7.  When it is time to create the S.O., its Release Date should be the Planned Order Release Date.  Therefore, the Need Dates of any Components should still be the MRP Planned Need Dates.  You should not see the S.O. Need Dates being pushed back as to describe.CAVEAT:  The S.O. Dates should be close to the MRP Dates if the Elapsed Time of the S.O. (i.e. Setup Time + Run Time + Machine Time + Queue Days + Move Days) through the Router is equal to the MRP Lead Time that you have defined for the F.G. Item.  If there is a significant difference between Lead Time and Router Time, then you will see the S.O. Need Dates move relative to the Planned Order Dates.
I suspect that you do not have Lead Time defined for the F.G. Item.  If this is true, then I would expect the MRP Planned Order Release Date for the F.G. Item to be the same as the Due Date.  That is, MRP will plan to have the Components available on the Day that the S.O. is to be completed which is way too late.  This sounds like what you are experiencing.  Then, when the S.O. is created, the Need Dates of the Components will be pushed back because of the Routing Elapsed Time which will be used for the S.O.
So, first thing, please check the F.G. Lead Time.
An additional technique that you could use if you want to push back the Dates for the Components is to set the Forecast Start Date to be before the Forecast End Date.  That is, currently the End Date is the Ship Date.  Set the Start Date to be 2 weeks before the End Date.  Then, MRP will create the Planned Order to be Due on the Start Date.  HOWEVER, I DO NOT RECOMMEND this approach.  You really should be using the MRP Lead Time to properly manage the Requirements.  

Please let me know if you have any questions.  Feel free to contact me offline to discuss these issues further.  I am a BPCS/ERP LX Consultant and I work extensively with MPS/MRP education, training, and consulting.  I would be happy to assist you further.

Thanks. 
Les Mittman
Cell: 847-858-5235

On Thursday, July 11, 2019, 8:59:20 AM CDT, jdholder@xxxxxxxxxxx <jdholder@xxxxxxxxxxx> wrote:

I'm a user/trainer/liaison for development of BPCS for 20+ years.  We have
attempted many times to resolve this issue with no success.  Just
wondering if anybody has seen this issue and been successful in coming to
a solution.

The problem......

We received forecast demand from our customers via EDI and is entered into
our BPCS MRP system in an automated process.  When MRP runs and plans
requirements for a forecast order, the requirements have a need date that
is equal to the date the customer requests the shipment.  This does not
allow for receipt of material early enough to allow for processing time.
When the order firms up, we enter an order (ORD500) and shop load the work
orders to produce the order.  When the work orders are created, the
backward scheduling parameters kick in and move the requirement date from
the date the customer want the order shipped back to a date that allows
for the process time represented by the values in Move & Queue days.  For
a product with a two week process time, the act of shop loading the order
(which takes the Move & Queue days into account) changes the need date for
the materials by two weeks.  We commonly firm the order and create the
work orders between two and four weeks before shipment.  This creates a
substantial change in need date close to the end of the life cycle of the
order.


The question.....

Has anyone experienced this problem?  If so, have you reached a solution
and what was done to resolve the issue?

Jeffrey D Holder
Chief Financial Officer


P.O. Box 349  I 160 Commerce Drive  I Bay Springs, MS 39422
Phone - 601.764.4121

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