It might help to explain the part of the building you have this transition in height. ie what you are coming from and going into etc. A lot of finishes in buildings result in skirtings and cornicings being terminated in a self return, in order to get around problems like yours. A self return can sometimes be easier to accept and live with rather than an obvious attempt to do something like that which you are considering. So its a choice on creating something obvious or something more discrete.