yeah that makes sense; for my house, one portion of my roof is two stories up. I am really comfortable on the 1 story high portion, but on the two story portion I start to get a little freaked out looking over the edge. Anytime I am up their, i.e. cleaning the gutters, I imagine myself falling off and breaking a leg or something like that.
The only way I would shingle the edge of that 2 story high roof is if I was standing on some decent metal scaffolding.