As counter-intuitive as this sounds, mathematical precision in cases hurts most candidates. Many candidates focus heavily on being mathematically correct because it is far easier to see if your answer of $230MM is the same as the prescribed answer of $250MM. It is human nature to focus on what can be easily measured versus focusing on what should be measured. Candidates tend to confuse mathematical precision with being analytic. They are not the same and candidates should focus on being analytic, as explained in this podcast.
