Currently, Other the option of disabling weekends from the timeline/duration calculation, Other non working days that are set in a work schedule (e.g. holidays) are taken into account only in the Workload widget.
I strongly suggest that non working days will also be taken into account in the duration, for example: If there are 5 working days in a work week selected by the user, and in the specified timeline there is a single non working day, then the duration will show 4 and not 5.