Always downgrade a little conservatively, except when reporting GOOD.
So MEDIUM-GOOD becomes MEDIUM for safety reasons, etc...
Too many times I've landed on a reported 1mm covered runway without seeing any lines under the snow layer and traversing over the ridges of snow rolling out, while reported to be MEDIUM-GOOD.
Wonder sometimes why airports give us pilots trying to land readings or measurements which are inaccurate to say the least, based on a runway inspection some time before landing during snowfall without intermediate clearing operations.