Spreadsheet, MRP or control tower: what each shows

The question behind the question

When a planner asks whether they need a new tool, the real question is usually narrower: which part will run short next, which late order matters, and where is cash sitting on the shelf. Three kinds of tools can answer some of it. Most mid-market manufacturers already use the first two.

1. The spreadsheet

What it is good at. Fast, flexible, owned by the person who uses it. A buyer can export open purchase orders, add a column for days of cover, sort, and have a chase list in an hour.

Where it stops.

• It is a snapshot: true on the morning it was built, stale by the afternoon.
• It depends on one person's formulas, and breaks when that person is on leave.
• It rarely joins more than two exports, so stock, usage, open orders and lead times are seldom side by side for every part.
• It does not show its own data gaps: a missing lead time quietly becomes a zero.

2. The MRP in your ERP

What it is good at. MRP is the engine that turns demand, stock, bills of materials and lead times into planned orders. It is the system of record, it runs on every item, and it is already paid for.

Where it stops.

• It trusts its parameters. If the planned lead time is a year old, every suggestion is built on it (lead-time drift).
• Exception messages come in volume: reschedule in, reschedule out, expedite. Many teams stop reading them.
• It reports late orders by date, not by consequence. The past-due report lists everything that is late, not the few lines that will stop a line.
• It rarely tells you which of its own inputs are missing or wrong.

3. A supply chain control tower

What it is good at. A control tower sits next to the ERP. It reads the same data, joins it across sources, checks it, and ranks the result: what will run short, which late orders matter, where value sits above target, and which data is missing.

Where it stops.

• It does not replace MRP. Planned orders, bills of materials and transactions stay in the ERP.
• It is only as good as the data it reads. A good one shows its data gaps instead of hiding them.
• It needs someone to act. Ranking a list does not call a supplier.

Side by side

• Parts that will run short: spreadsheet, if someone builds it today; MRP, implied in planned orders and messages; control tower, listed and ranked with the evidence.
• Late orders that matter: spreadsheet, manual sort; MRP, all late lines by date; control tower, late lines ranked by severity with cover as evidence.
• Lead times out of date: spreadsheet, only if you compare by hand; MRP, not flagged; control tower, planned versus current lead time compared.
• Stock above target: spreadsheet, possible with effort; MRP, not its job; control tower, item by item.
• Missing or wrong data: spreadsheet, hidden; MRP, mostly hidden; control tower, stated as such.

How to tell which gap you have

Run this check with two exports you already have, stock by item with usage and open purchase orders with dates:

• Count the parts that ran short last month. For each, ask: did the MRP or the spreadsheet show it coming a week before? If yes and nobody acted, the gap is process, not tooling.
• Count the open lines without a confirmed date. Above a few percent, no tool will be accurate until confirmations improve.
• Compare planned and measured lead times on your top 50 purchased parts. A large drift means MRP suggestions are late by design.
• Time the morning routine. If building the chase list takes more than an hour a day, or depends on one person, the spreadsheet has reached its limit.

Illustrative example, not a customer result

A plant with 2,000 active purchased parts runs MRP nightly and a buyer rebuilds a shortage spreadsheet every Monday. Last month, 6 parts ran short. For 4 of them, the planned lead time in the item master was shorter than what the supplier now quotes, so MRP ordered late. The spreadsheet caught 2 of the 6, because it was built on Monday and the shortages hit on Thursday. Here the gap is data and frequency: correct lead times, and a list that is rebuilt every day, not every week.

Where WERISCO fits

WERISCO is an AI supply chain control tower. It connects to your ERP or works from the exports you already run, and shows parts that will run short, ranked by days of cover, late or undated supplier orders flagged by severity with each part's days of cover shown as evidence, stock above your own target levels, and the data gaps that block the analysis. It does not replace your MRP or write back to your ERP; your team decides. See a sample result on demo data.

Questions people ask

Is a control tower the same as an APS?

No. An advanced planning system (APS) plans: it optimizes production and purchasing against constraints. A control tower watches and ranks exceptions on the data you already have. Some vendors offer both.

Do I need to replace my spreadsheet?

Not necessarily. If your list is rebuilt daily, joins stock, usage, open orders and lead times, and shows missing data, it may be enough. The check above tells you whether it is.

Can MRP exception messages do the same job?

In part. They are triggered by the same parameters, so if lead times or stock records are wrong, the messages are wrong too, and they do not rank by consequence.