In enterprise commerce, totals don't drift because someone forgot algebra. They drift because reality changes: promos expire, eligibility changes when an address arrives, catalog data updates, substitutions happen, and returns unwind prior discounts. When someone asks "why did the total change?" you need more than narration. You need evidence - a trail of facts you can replay and a pure computation that deterministically produces the same result.
We are now in a time of manufacturing where precision is more than a technical necessity; it's a business requirement. The more complex, globally dispersed and demanding things get, the less slack remains in the system. Under these circumstances tolerance management has become a decisive competence and affects competitiveness not only in terms of controlling costs, ensuring quality and improving production efficiency but also for long term market success.
