In addition to primary costs, secondary costs are often incurred during the production of cost center activity. This is because a cost center must often take activity from other cost centers to produce its own activity. Secondary costs on the cost center result from internal allocations, such as activity allocations or assessments.

To get meaningful periodic comparisons of plan and actual data, you must plan secondary costs as well as primary costs. You can plan secondary costs as value-based (assessment or order settlement) or quantity-based (activity input).