The advantage of this approach is that joint cost allocation will not produce consistently profitable or unprofitable items.The rationale for using ability to bear is the assumption that costs would not be incurred unless the jointly produced products together would yield enough revenue to cover all costs plus a reasonable return. On the other hand, fluctuations in the market value of any one or more of the end products automatically change the apportionment of the joint costs, though actually it costs no more or no less to produce than before.