This article takes a four-foot masonry opening and breaks down the cost to properly flash the masonry opening versus random techniques performed by some estimators. This example references estimating against production changes to cover costs.
Estimating has many different methods. Restoration estimators are typically part commercial estimator, part restoration, and part magician. I have seen million-dollar jobs estimated and summarized on the back of an envelope and others on spreadsheets that NASA could not even follow. There is not just one type of restoration estimator, but we all have the same goal: understand cost, plan labor methods, and make money.