Help!: Doubling back on part of a route?

How do you place points on a previosly traveled (plotted) portion of the route? In other words, my route goes for about 4 miles, then makes a big loop, and returns to the starting point on the same 4 miles I went out on. The plotting tool doesn't want to let me plot more points on that stretch of road previously traveled. Does that make sense? As far as drawing the route, it looks great, but the distance and elevation don't get accounted for. Maybe I'm missing something?