Because of multitask assignments, cross-training, and redeployment of other support personnel, most support costs are exclusive to a focused value stream and are thus assigned to a product using direct tracing. One consequence of increasing directly traceable costs is to increase the accuracy of product costing. Directly traceable costs are exclusively associated with the product and can safely be said to belong to it. Product cost is calculated by taking the costs of the period and dividing by the output. For example, suppose that the costs of the value steam are $80,000 for the month of January and the output for January is 5,000 units. The unit cost is $160 per unit ($800,000/5,000). Focused value streams are the most accurate and simple possible.