It may seem like an unnecessary task to check the numbers your experts extrapolate from an exhibit and put in your charts and summaries. However, someone must. Based on one sorry experience of my own, I want it to be me. With inter-related exhibits that march towards the conclusion in a damage case, such an inadvertent error could at worst knock out your damage calculations and, at best, hurt the witness and your side's credibility. DON'T play the expert's home court game in cross examination.
Experts are experts for a reason.
They are schooled, experienced, and often tested in the pits of trial. For example, unless you are utterly remarkable, you do not know economics like someone who works in the field every day, has a doctorate, and has been teaching it for years. Too often attorneys dignify the expert and actually improve the expert's credibility by cross examining directly on the points of the expert's opinions. That is not to say that an expert cannot be successfully cross examined and that their opinions cannot be called into question, even demolished. But if caution is the better part of valor, you likely can make up more ground if you attack collaterally, focusing on such lucrative areas as the assumptions on which the opinions are based or the things the expert did not consider.