In principle historical costs should be attributed to individual units of production, although admittedly the cost plus method may over- emphasize historical costs. Some costs, for example costs of materials, labour, and transport will vary over a period and in such a case it may be appropriate to average the costs over the period. Averaging also may be appropriate across product groups or over a particular line of production. Further, averaging may be appropriate with respect to the costs of fixed assets where the production or processing of different products is carried on simultaneously and the volume of activity fluctuates. Costs such as replacement costs and marginal costs also may need to be considered where these can be measured and they result in a more accurate estimate of the appropriate profit ...

In principle historical costs should be attributed to individual units of production, although admittedly the cost plus method may over- emphasize historical costs. Some costs, for example costs of materials, labour, and transport will vary over a period and in such a case it may be appropriate to average the costs over the period. Averaging also may be appropriate across product groups or over a particular line of production. Further, averaging may be appropriate with respect to the costs of fixed assets where the production or processing of different products is carried on simultaneously and the volume of activity fluctuates. Costs such as replacement costs and marginal costs also may need to be considered where these can be measured and they result in a more accurate estimate of the appropriate profit ...