Factory specs are set on the safe side to reduce complaints and returns/ warranty work. String height is a personal thing that differs from person to person. I don't really know the actual measurements I prefer as I dial it in by feel. That's the best way to go imo. Measurements are useful if you cant get a comfortable action and think there might be a problem with the guitar due to fretting out or are trying to advise someone else who's setting the guitar up for you. Still not ideal. The player should know what he likes better than anyone.