Usage and Grammar

Q. One of my authors uses “as noted by” and “as is noted by” frequently. I assume they are the same. However, my copyeditor changes some of the “as is noted by” to “as noted by” but not all of them. Are there differences between the two phrases? I read the sentences over and over again, and I can’t see the difference in meaning before and after the change. If there is no difference in meaning, why change it?

A. The phrases mean the same thing, and there is no need to change them unless either or both are being overused. But sometimes copyeditors get twitchy if they can’t change something for a while. Maybe if the author’s work had contained more typos and other problems, the editor would have left these alone.