Costs to Complete for Internally Processed Activities 
Prerequisites
The activity is assigned to a WBS element.
The activity must be flagged as "costing relevant", using the control key.
Features
The updated residual costs (or "costs to complete") are calculated on the basis of the forecast work still in the internally processed activity, or the residual work in the cost forecast.
The system determines the costs to complete as follows:
The activity has not yet been confirmed (no actual dates).
The system recalculates the planned costs in the activity and records them as costs to complete in the forecast version. The estimated costs at completion are the same as the costs to complete.
The system uses the distribution key in the activity to distribute the planned work to the period between the key date in the cost forecast and the planned activity finish. The system recalculates the planned costs in the activity on the basis of the changed duration and records them as costs to complete in the forecast version, by period. The estimated costs at completion are the same as the costs to complete.
All of the planned work for the activity is valued in the period of the key date.
The activity is partially confirmed (actual costs exist).
When an activity is being confirmed, either you enter the forecast work manually or the system determines the remaining work (forecast work) based on the percentage of completion (POC). If there is no forecast work the system calculates the residual work by deducting the work actually performed from that planned. In addition, you can enter the forecast duration or finish in the confirmation.
The forecast work is distributed and valued in the activity per the distribution key, to the period between the actual date from the confirmation and the activity finish date. The finish date is determined in the following order:

The activity is finished or a final confirmation has been entered for it.
The system sets activity costs to complete at zero. You do not expect any further costs in the activity. The estimated costs at completion are the same as the actual costs in the activity.