Very few people actually take a close look at the cutting edge of a chain/cutter, if they did then they could see what the cutting edge actually needs to look like but since it is kind of on the underside of the cutter most just hope the file or wheel magically makes a good sharp cutting edge. When I taught hand filing it became very apparent to me why so many sucked at it, providing them with guidance, clamp on filing guides and hours of instruction made a very few good chain sharpeners. Only by closely examining the cutting edge can one become proficient at sharpening, I say do whatever the particular chain requires as not all chains are made the same.