Purchasing Suggestions creating spurious postpone/reduce triggering MRP

Since we migrated to E10 a month and a half ago, we have started noticing very weird behavior with MRP and purchase suggestions.

One of the things we are seeing is that there will be an approved, confirmed PO in the system for a certain material, but “Generating Purchasing Suggestions” will suggest that we postpone the PO (in some cases, for over a month!) and then suggest the PO again, and then immediately “Increase” the amount of the PO by a negative amount, effectively reducing the PO quantity. Subsequently we have demand for that PO through a job in a couple of shipments which the new quantity is insufficient to meet, so MRP is generating jobs to fill that demand. But the initial PO already met demand in the first place! As a result, we are getting purchasing suggestions for many parts which we have already have sufficient POs on file to handle, resulting in wasting a lot of time looking at these suggestions only to realize that they are completely bogus.

As far as I know we are doing everything exactly the same as we were in E9. We have a support case open for over three weeks with multiple WebEx sessions with various things tried but no resolution of what is going on. For instance, we were given a fix that is supposed to look at the PartDtl table for records of type “TO” which were incorrectly left over from closed TFOrdDtl records - only there are no such records in existence.

I have also tried experimenting with various combinations of options to “Generate Purchasing Suggestions” in a sandbox copy of the database, but the suggestions just won’t go away.

Has anybody experienced this or have any idea what could be causing it?

Wow, this sounds like a similar problem that happens if you don’t have the “new” (sometime in E9) setting for “Allow Consumption of Minimum”. Search this out in the Help file, and my recommendation is that this setting should be TRUE. When you have this turned off, the system treats Minimum qty oddly, and will do exactly what you have described, especially if you have no future demands. ie… if you are simply below the minimum, it will give a buy suggestion, then after MRP runs, it will tell you to reschedule. when you do… it will trigger another suggestion to buy more and cancel the old PO.

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I also like that “Allow Consumption of Minimum” = true
will include a parts Lead Time in the Due Date calculation for new suggestions.

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Thanks, I’ll take a look at that! If this isn’t new in E10 this wouldn’t be the first setting that didn’t migrate properly.

Sure enough, that checkbox was not checked. (The help file was no help in even finding this checkbox, but from another comment on this site I found it is in “Site Maintenance”). But after checking it and re-running “Generate Purchasing Suggestions” and MRP I am still seeing bogus suggestions.

I was going to see if this field had been checked in E9, but I can’t even find Site Maintenance in E9…

Oh… I noticed in my initial post that I only mentioned one of the weird things it is doing. The other is that we have parts that have no (0) min on hand, sometimes we will have none in stock and sometimes we have a handful. On these we are getting odd combinations of “Suggestion for Warehouse” and MRP generated jobs. For instance:

I think these MRP jobs are related to (are used as materials in) parts that have jobs scheduled which are having the first issue of postpone/suggest/reduce.

Here’s another example of how suggestions are messing things up.

We have a part that has a min on hand of 100 with a lead time of 21 days, but currently there are only 75 in stock. There is a PO that is open, approved, and confirmed, for 250 pieces, entered 9/3 and due 10/10. Further, there is a job for stock that is released and scheduled for tomorrow which will consume 50 pieces.

Without suggestions, the time phase looks like this:

So it seems obvious that this part is in good shape - the replenishment is going to be a bit later than we would like so we are going to be below min on hand until the ordered quantity arrives, but otherwise things are ok, we are not going to run out.

Now with suggestions we get this goofy mess:

It’s suggesting that our open PO somehow arrives immediately, despite the fact that it isn’t going to arrive for over a week. Then it immediately reduces the amount of the PO to just barely cover the min on hand. After this, the F job depletes stock to below min on hand, but the original PO… I’m not sure what is even happening here, because immediately after it shows up there is an “expedite” which cancels it out. I can only assume that this is because it previously decided we should get the order before we can get it, so now it needs to cancel the original date out of the system. But at this point things are still below min on hand, yet it doesn’t suggest any more under over three weeks later, and not even in a quantity sufficient to meet min on hand. So if it suggested the PO faster because it somehow wanted to replenish the min on hand faster it immediately failed at that as soon as the F job consumed stock, because it never replenishes sufficiently after this to meet min on hand!

None of this makes any sense. The suggestions are causing the part to show up in a list of parts that need attention, which wastes purchasing’s time reviewing this only to see that no, this part is already on the way. Furthermore, it winds up having less on hand (and below the minimum) than if the suggestions had not been made in the first place!

I’m noticing in some of the parts I’m looking at, that a PO will be in process and scheduled for the part to arrive on a certain date, but the suggestion will be for that same PO at an earlier date. Is there some possibility that it’s getting confused? It seems to be demanding that the PO be rescheduled for an earlier date than is possible (if the part is on order and isn’t arrive for another week or two, there’s no way that it’s going to arrive tomorrow like the system seems to be wanting it to). And then after that things seem to be going off the rails as it does this weird juggle with the same PO trying to get the balance to end up right, and often failing miserably.

This still looks like it is processing like you dont have the “Allow consumption of Min” turned on. The fact is that you are below min, AND you are consuming more taking you even more below min before the next PO is scheduled to arrive. Allow consumption is supposed to take the lead time into account… so as long as the supply is arriving before the leadtime, it should not suggest anything…
Tell me… what is the setting on MRP for teh “Schedule Start Date”… is it “TODAY” or sometime in the past? If it is not today, but a month ago, it can cause really weird things… This is easy to do if you have MRP on a scheduled process and you didnt click the “Dynamic” box:
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two more things to do/check:

  1. check out the “Reschedule In/Out” delta fields… these are visible in Part/Sites/Planning as well as the more global settings in the PartClass Maintence (which allows you to control this for a whole group of parts). This setting is what I call “Noise Reduction”… you can tell MRP to ignore any reschedule notices if within this in/out delta range.
    image
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  2. Also, consider LOCKING the Schedule and Quantity on the PO… this will eliminate all future change suggestions to this PO. Note that it will NOT eliminate NEW PO suggestions even when you have a future PO… so that is why the “Allow Consumption” setting is so important.

@timshuwy I would beg to differ that locking a PO allows new suggestions…

Would not surprise me.

I wish there were clear answer but… determining the reasons behind change suggestions can be an unrewarding exercise.
For one thing, system planning settings are spread all over the place, e.g. company, part, classes, sites, etc…
It gets more complicated if you have users who are changing any demand/supply dates.

In my case I ended up making a dashboard to help track CHANGE suggestions.
Then played around in Test with MRP/GenSuggs using different runtime options and modifying the planning settings for parts/classes/sites until I started seeing (slightly) better results.
And as an Epicor support tech once told me… “they’re ONLY suggestions”. Which is true but, didn’t make me feel any better about them

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