This post will explain how the Reschedule In/ Out Deltas work in Epicor MRP and covers version 10.0.7 and 10.1.6.
What do the Deltas Do
When I first looked at these parameters I was hoping to use them as a way of stopping expedite and postpone suggestions as for the project I was one, once an order had been placed, it was not realistic to expedite or postpone PO's.
My understanding was that the reschedule in delta specifies the number of days that a due date must be outside of to be expedited. Thus if I set a part to have reschedule in delta of 365, then any purchase orders with a due date within the current date + 365 would not be expedited.
Similarly, the reschedule out delta defines the PO's that can be postponed. Thus a reschedule out delta of 365 would ensure that PO with a due date within he current date + 365 would not be postponed.
Real World Implementation
Initially, I was really pleased with the way the delta seemed to be working.
No expedite or postpone suggestions were generated.
All was going well, however, after a few MRP runs I started to notice that even though all parts were flagged as 'Restock to Max', the quantities in the new PO suggestions were not taking stock back to maximum.
In trying to investigate this I set the deltas to zero to see what would happen and when I looked in time phase, everything stacked up and the quantities on the new PO suggestions were unchanged.
All the deltas do is delete any expedite or postpone suggestions within the delta periods at the end of the MRP run
The expedite and postpone suggestions are used in the MRP calculations, therefore, you run the risk of new suggestions having invalid quantities.
In order to resolve this in 10.0.7, I locked the date at PO release level. however, in 10.1.6, the locking of dates does not work (PRB0190396) in this context.
Thus in 10.1.6 I have had to create a dashboard for the users that lets them know the PO suggestions that are understated and by how much.
It would not take too much to automatically use this information to update the PO suggestions to the correct value after the MRP run.
According to Epicor the reschedule in/ out deltas are working as expected. Thus, all they really do is delete suggestions within a time period.
It is almost the same as the 'Planning Time Fence', except that it does allow new suggestions to be created.
In 10.0.7 locking dates at the PO Release level is the only way to stop the expedite and postpone suggestions and also ensure that the quantities in the new suggestions are accurate.
However, in 10.1.6 this functionality is not available to due a bug which is currently being worked on by development to be delivered in 10.2 and hopefully will be retrofitted in 10.1.6.
In short, if you want to lock dates and run MRP in 10.1.6, then your going to have come up with a contingency (i.e. dashboard) to ensure the correct quantities on your new PO suggestions.