Topic
Formula engines, configure-price-quote, and why made-to-order businesses live in Excel.
12 articles
Pricing is where the business logic of a made-to-order manufacturer actually lives, and it is almost always in a spreadsheet that one person maintains. That is not incompetence: the spreadsheet can express what the business does, and the software usually cannot. A system that only lets you pick a price from a list has not understood the trade.
So the work here is about giving the formula back to the people who own it — a pricing language the business can read, rates that are dated, a calculation whose working is stored rather than only its answer, and the same expression evaluated twice so that cost and selling price never get mixed. The recurring discovery is that once the working is stored, features nobody had asked for become nearly free.
Dimensions and features already sit on a quote line. Turning them into geometry needs an archetype layout and a registry keyed by code, not a modelling pipeline.
Every pricing rule assumed inches. The customer wanted to enter millimetres. Converting at the API boundary was the only change that could not corrupt old quotes.
Thirteen of 362 pricing rules needed to call other rules and branch on a dimension. Keeping the language to CALL and CASE is what kept it safe.
One made-to-order product had 24 features and 62 variants. Pricing at product level is combinatorially hopeless; pricing per feature is not.
What auditing a fabricator's quoting workbook revealed about how bespoke pricing really works, and which parts of it a person was silently holding together.
The output document is a specification. Reading real ones confirmed eight pending requests, produced several more, and settled two arguments about tax.
Knowing what to charge is not knowing whether the job is worth taking. Two evaluations through the same rules give per-feature margin without a second engine.
The CAD files looked like the authoritative source for dimensions and geometry. They were neither. What they were useful for was checking the formulas.
A completeness dashboard counted every variant of every feature as required. The import was fine; the counting rule was wrong, and it hid the real gaps.
The source workbook had two formula columns per row, one per grade. That single detail decides how a bespoke pricing engine has to resolve rules.
362 pricing formulas, none of them in the source code. How to evaluate business-authored expressions without eval, and why that boundary matters.
Bespoke manufacturers price in spreadsheets for good reasons. A governed pricing engine keeps the flexibility and removes the drift.
