Some costs cannot be linked to products based on causality, and they may not be employed to judge the drivers accurately by contrast between benefits and costs, thus they are assigned on the basis of fairness or reasonableness.

• 有些成本可能难以依据因果关系确定,或者是无法根据收益与成本的比较来确定,那么,它们就需要根据合理性或公平性来进行分配。