RE: BNC and Missed DeadlinesIn business, almost any date is plus or minus a few days.
(Or a few weeks depending on the size of the work to be completed.)
Everything always takes a bit longer than people estimate. Usually people estimate the best possible case, which almost never happens.
Especially managers, who are naturally optimistic. If you want a good estimate, hire a pessimist, and you might even get it earlier than the date. However, pessimists are out-of-favor at companies because they are perceived as downers and doubters.
Similarly costs are almost always underestimated, even after decades of modern business practice.