Trace Shop Order Demand

A direct link with the whole chain sounds like beyond the scope of classical make to stock planning such as MRP. It will be always a gross supply vs gross demand. There are other parameters in the calculation such as netting, lot sizing rules, etc that further dilute the possibility of having a direct link end-to-end. The more levels MRP has to dive down (e.g. 3 or 4 level BOM), you will see that then MRP indicates the source as “MRP Planned Demand”, due to the inherent way MRP works.

I’d say depending on how critical building this “link”, you’d have better chance using a proper MTO planning such as DOP (Dynamic Order Processing). DOP has its own negatives, such as being too nosy, but you could have a DOP and MRP mixed planning to have best of both worlds. If DOP is out of the question, possibly refining manufacturing setup to cut down some levels, and use manual pegging where possible would help you get a better shot at finding this elusive link. You could also try if MRP Action Proposals would be help too.

I had about same request, but another way, customer ask possible SO’s for COL. (much easier case as you have). As there is no direct unique links, I made custom fiels what shows all possible SO’s, and that was fine for them.
Maybe you can do something similar but another way.

SELECT LISTAGG(SO, ' ; '|| CHR(13)||CHR(10)) WITHIN GROUP (ORDER BY SO) SO
FROM
(
SELECT order_no||' - '|| state||' - '|| revised_due_date||' - '|| revised_qty_due||' Qty' SO
FROM shop_ord
WHERE objstate NOT IN ('Closed','Planned','Cancelled')
AND contract = 'xxxxx'
AND part_no = :part_no
)

The Finance Department wants to differentiate between stock demand and customer demand for inventory grading. My concern with not diving deep enough is that grandchild parts will look overstocked when they're actually necessary to build in-demand parent parts. They agreed, but we weren't sure how easy this would be to do.

Relying on a custom field with manual entry assumes the data is mostly complete. This is a subtly different need than tracking the most important orders.

Fortunately, my further analysis found this isn't a critical issue most of the time, since grandchild shop orders don't spend a lot of time in limbo between release and reservation.