I just took the bike off the work stand. I won't call it user error... rather I'll call it not being informed. The front lever moves the chain one cog at a time. The rear lever does indeed move it four at a time if you push it that far. Pushing it with my thumb as far as I could without re-gripping or stretching, was downshifting two gears at a time. It seemed like the right distance to push it to me. If Shimano has that information on their site, I couldn't find it. And Trek's owners' manual doesn't mention it. And neither did the sales guy. Learning curve. My last shifters were grip shifters.