I found this blog post interesting:
http://www.ilona-andrews.com/ku-availability/
It's by Ilona Andrews (husband and wife team, best known for their conventionally-published Kate Daniels distopia/romance series, but also with some other series) and is about the economics, for them at least, of KU for their non-traditionally published titles. They also talk about the assumed economics for other authors who write differently (faster) than they do.
If you don't want to read the post, the short summary is "no" - KU doesn't work for them. They acknowledge that it might work differently for some other authors.
Anyway, I found it an interesting analysis...