By choosing General data for a selected period, you can see which plants are assigned to a costing run, which plants can still be assigned to a costing run, and which plants may no longer be selected in the period.
Before you perform multilevel actual costing, select the plants you want from the selection window Available Plants. For each period, a plant can only be assigned to one costing run. If you have already performed a flow step for a costing run, you can no longer change which plants are assigned to a run. You can only change the plant assignment if you completely delete the costing run. For more information, seeDeleting a Costing Run.