Walter will appear to have performed poorly relative to the initial estimated unit costs,while Mary will appear to have performed extremely well. However,as shows in part c, Mary's true cost of producing a metal cabinet would have been $1.67 higher than the initial estimates if the machine were purchased. Since there would be no real change in the resources used by Walter to produce wood cabinets,his cost per unit should equal the estimated amount.Thus,the total unit costs as calculated is part a would not be a fair or accurate representation of either manager's performance.