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.
Probably enough said already, but in general the skirting will follow on from the wall string depth, which goes beyond the nosing line. Not by much between an inch and two in most cases. Most Victorian houses simply laid out straight skirtings and did the easing with kerfed staff beadings. Most of which were curved easings. So what i think would look 'odd' is having the skirting clear the step by its full depth, which you simply don't see going on in general. Which I think is what you are instinctively pondering about. If you have already done your main skirting runs, then you might find that you are cutting into the moulded top to keep within the conventions.
No I didn't. The original was not the correct angle, the edited was. Do I need to draw you another picture? And do you take angles by hand, off the 90º cut? No. Does your mitre saw have a setting for a 90º cut? No. Or is the 90 a nought? Yes. So the mitre saw is wrong(as they all are). Mr. HandyAndy - Really
So which of these have I got wrong? "And do you take angles by hand, off the 90º cut? No. Does your mitre saw have a setting for a 90º cut? No. Or is the 90 a nought? Yes." Mr. HandyAndy - Really