Follow up: One of the papers I resubmitted after an R&R where I had to write a 6,300 word memo was rejected. One of the reviewers decided that the language and paper structure that he (it is probably a he) suggested that we use last time wasn't good enough, and that we should rewrite the whole thing again.
In case you're wondering what my first experience at Sociological Perspectives was like:
All R&Rs, no matter how much work needs to be done, must be returned within 60 days. The editor is sometimes willing to give you a 3 or 4 day extension, and that's it.
The reviewers (I had) are micromanagers who want to rewrite the paper for you, and in at least one case, will forget what they told you to do the last time.