I think it was helpful at least. We would have figured it out anyway, but it was nice to stay away from the middle.
I just realized why I was surprised looking back at the height after we passed through there. That index contour seems to go straight through the cliff, but it's actually the next lower one that comes out the other side. Definitely a 5-contour cliff.
This picture is at 3, you can see the cliffs on the right ~150m away.