How do you deal with difficulty based on direction? 18" drop is a lot harder (for me at least) to ride UP than down. I just think back to Austin and Emma Long (likely a single black). I got to the point of riding down everything, but up was another matter completely.

Do you have a different trail rating for each direction? This stuff doesn't apply to other down[hill/stream] activities. Even rock-climbing rating is generally based on one direction.

I guess if it's technical one way, it's technical the other. I guess I'm answering my own question here. An 18" drop is 18" down or up, so be it. Aerobic difficulty should be on a different scale, and not consdered here.