Why is "-11%" rendered as "Moderate"? Everything <0 should be "Easiest", shouldn't it? Or maybe even add another category, "Downhill"? Also, any idea why this

Why is "-11%" rendered as "Moderate"? Everything <0 should be "Easiest", shouldn't it? Or maybe even add another category, "Downhill"? Also, any idea why this doesn't work for Berlin, Germany? You could at least show the ZERO_RESULTS status somehow.