Hi Mark - The best thing I can suggest is to have a look at our video tutorial on Editing Routes - this should hopefully help.
I'm trying to figure out how to add a point between two way point. For example lets say I'm trying to plot a 10k route. After ploting a route I find out I'm only at say 9.5km. In order to add the extra 0.5 km I need to make a few small (or one big) sidetrack from my current route. I've tried the "drag mode" on, which will allow me to drag a point from my current track to a diferent road, however the auto-pilot ends up re-routing other parts of my route. I've tried draging the "A" and "B" points closer together, but they are very hard to control and often end up jumping to a completely different area.