In response to another question @Luke has referred to the APQ stat (ratio of answers per question) as a measure of the quality of the site.
I have noted in several places (and done it myself) a comment added to an existing good answer to provide an additional item of information that supplements what was originally written.
If that becomes common practice it will depress the APQ. (It is currently 2.77. If just one comment on half the questions had been a separate answer, it would be 3.26).
Would it be better to create a completely new answer that links to, and extends, the first. Or would that be against the spirit of the SE model?