Route planner - type of route/surface

At now if I change type of road/surface it aplied to whole road. Please add a checkbox 'whole route' (or 'last point only'). If 'whole route' checkbox will be checked, changing type of prefered road/surface will works as now. If checkbox will unchecked, changing type of road/surface will affect only for route from last point to previous.
With this there will be a possibility to plan mixed type of road. It would be very useful for 'gravel' or 'touristic' type of rides, where I very often mix many type of surface.