How should the shoulder belt be routed in booster mode?

The shoulder belt must be routed over the child's shoulder and pass under the headrest between the headrest and the seat, as long as the child's shoulders are at or below the opening. If the child's shoulders are too high, the belt should be routed on top of the headrest. The belt must cross midway between the child's shoulder and neck and not cross the child's neck or fall off the shoulder.