I wouldn't rely on that dot too much, because it is assuming that conditions won't change. Almost always, when you are approaching terrain, the wind WILL change and then the dot will have mislead you. It is much better to have a mental picture about wind direction and aerology and the resulting winds, and to look out the window. If you start to see more things behind the hilltop as you approach it, you are above it; if you see less, you are below.
Also, don't fly towards a crest head-on, and be prepared to turn back if you find yourself too low. If you want to fly accordingly, the dot will be of almost no help.