When the supersession lives in a spreadsheet, the old part still wins the lookup

Replacement chains that never make it into published catalog data leave the discontinued part in the bay and the current part invisible at lookup.

Most catalog teams know which parts supersede which. The problem is where that knowledge lives.

If the chain sits in a purchasing spreadsheet, an ERP note, or a supplier email thread, the published ACES file still points customers at the old part number. Lookup succeeds. Inventory for the replacement sits. The return or lost sale shows up later as a “catalog” problem even when everyone on the team already knew the part had moved.

Three places the chain breaks.

The file never got the replacement. ACES can carry supersession relationships, but only if someone writes them in. A one-time cleanup that maps applications and attributes can still leave successor links out. The discontinued SKU keeps its applications. The new SKU may have none—or only a partial set.

The receiver never saw the update. Even when your internal catalog is current, AutoZone, NAPA, O’Reilly, Amazon, and Advance Auto only see what you deliver. A supersession that exists in your warehouse system but not in the last file you sent is invisible at the counter and on the marketplace.

The chain is longer than one hop. Part A to part B is easy to remember. Part A to B to C, with overlapping sell-through windows, is where manual lists drift. If only the last hop is documented, older lookups still resolve to A or B after both should be gone.

A practical supersession habit is small and regular.

1. Treat supersessions as catalog data, not purchasing trivia. If the replacement is real, it belongs in the same place applications and attributes live.
2. Check both ends of the chain. The old part should stop winning live lookups when it is no longer the part you want sold. The new part needs applications, attributes, and images that match what you actually ship.
3. Review on a cadence. A monthly pass over new replacements, supplier notices, and high-return discontinued SKUs catches drift before it compounds. Waiting for a full recatalog lets wrong part numbers stay live for months.
4. Deliver the update to every receiver that still has the old mapping. Internal correctness does not help if the last accepted file still lists the discontinued number.

InterWest Technology Group manages part supersessions in catalog data and issues a monthly supersession report so replacement chains stay in the published file—not only in a spreadsheet.