The markup stack that broke in May

In May of 2026 I shipped a bid for a quick-service restaurant client off the estimating engine I built, and the markup stack was wrong. Overhead, profit and contingency were stacking on top of each other instead of each one hitting its own base, and the number that came out the other end was $785,000. High enough to lose the job on price, or worse, lose the client's trust if they ever ran the math themselves. I sent it because the engine had been right on the smaller jobs before that one, and I trusted the pattern instead of walking every line myself. That is the real mistake. Not the code. The decision to skip my own check because the tool had earned some trust. We caught it before the client acted, rebuilt the stack so every percentage sits on its own base and prints as its own line, and got a corrected version out the same week. What I do differently now is simple. Nothing I build leaves the building on one pass. Mine included.