Why your quote is wrong when you change the steel grade

You quote the same stainless table in a heavier grade. A quoting system that only swaps the price per sheet will give you a bigger number, and for most items that is right. For some items it is wrong, because in a heavier grade the item is made differently and the arithmetic itself changes. The quote looks reasonable, goes out, and is wrong in a way nobody will spot until the job is costed.

We found this in the pricing workbook of a fabrication business. Every product-and-feature row had two formula columns, one for each grade of stainless the business quotes in. Same product, same feature, two different rule codes.

What was actually going on

I had assumed grade was a rate: pick the cheaper sheet and the same calculation produces a smaller number. That is true for most features. It is not true for all, and the difference is not cosmetic.

So the system has to support two ways for grade to affect a price, and they behave differently under change.

Grade changes the rate. One rule, and the grade decides which material is picked. A cheaper sheet has a lower rate and the price falls. The rule is untouched. This is the common case, and the business maintains one calculation.

Grade changes the rule. A rule can be pinned to a specific grade, so the same product and feature go to a different calculation depending on the grade on that line. This is the minority case, and it exists because the workbook said so.

You cannot pick one. Supporting only the first cannot express what the business already does. Supporting only the second forces a separate rule for every feature and doubles the number of them for no benefit.

What we changed

With both live, a lookup can find several candidate rules, and something has to choose. The choice runs in three steps. A rule pinned to this line’s grade beats one that names no grade. Then a rule pinned to the exact variant the customer chose beats one with no variant, which beats a catch-all that exists as a fallback. Ties are settled by a priority number on the rule. This works, and it is hard to debug, because the rule that fired leaves no trace in the output unless you put one there. So the system also flags the case where a suitable rule existed but was not the one chosen. That is not a data problem for the business to fix. It is a fault in how we choose between rules, and it is reported as one.

Grade also drives something less exact. When a rule needs a material and nobody has picked one, the system picks for them, scoring candidates by whether their description matches the grade, states a sheet gauge and matches the preferred one. That is text matching against product descriptions, which is a guess, tuned to how this business names its stock. So it is never the only path: what it chooses is visible and can be overridden, and the calculation records which material was actually used.

The business’s own request, once they had used it, was to hide the material pickers. A salesperson quoting a standard item in a standard grade should not be looking at a list of sheet stock. Material selection now appears only when the user chooses a custom-grade mode. In the normal path the defaults apply silently. The same request covered dimensions: show a field only where the estimator must enter something.

What it did not fix

Grade-pinned rules and rate-driven grades coexist, and nothing in the system tells you which mechanism a given product and feature uses. You find out by looking at the rules. For a catalogue this size that is survivable. For someone maintaining it who did not build it, it is a real gap, and the honest position is that the rules need a view that answers “how does grade affect this feature” directly.

No wrong quote is counted here. The article is about how the system decides which rule applies, not about a loss it caused.

The pattern, for anyone who prices by material or variant

Before you add an option such as grade, finish or region, find out whether it changes an input or changes the calculation. Ask for the source spreadsheet and look for a second column. If both happen in your business, both must be possible, and the order in which they are resolved must be written down and shown in the quote.

Configurability is for the person maintaining the system, not for the person using it eight times a day.

Where this ends up

Both mechanisms coexist in Quote: a grade that changes the rate, and a grade that pins a different rule, with the choice between them settled by how specific the rule is, not by convention.