4. Under what circumstances would the number of equivalent units of materials differ from the number of equivalent units of labor and overhead in the same department in the same period? Under what circumstances would they be the same? 5. Units are usually assumed to be at the same stage of completion for both labor and overhead. What is the reason for this assumption? Would an automobile plant that makes specialty race cars use job costing or process costing? Would an automobile plant that makes all-terrain vehicles use job costing or process costing? Explain your answer 6