In 2008 I wrote some VBA scripts and built an Access database as part of a dashboard used by suits at an insurance company to track sales stats. Pretty sure it's still in use. The suits also made a decision to open a third call center based on some staffing and cost analysis done by me and my boss. We used two totally different models (and argued a lot about which model was right). The director said, "The conclusions…
That's intriguing... Some obvious questions are: if you had known, would you have spent more time or just been "more serious?" Would you have had better answers after more time? Did the other person do the same level of rough estimate, but with a different model?
The other person's model used a different approach to the problem, using variables that I completely ignored. Turns out he had been sweating over this problem for a couple of weeks, googling for methods and models and massaging some complicated VBA program he'd built. (He loved VBA, go figure.)
When he got to his answer, I said, "OK, now add 10%." He exploded, "That's what drives me nuts about this! Every paper takes you through all this complicated math and detailed calculations, then at the end they say, 'Add 10%'! What the hell!?"