aakk9999 - 4:30 pm on May 13, 2013 (gmt 0)
I had a similar experience: added authorship to a website that already held #1 for its main keywords and the CTR dropped. I have since removed authorship from the home page, but left it on "About us" page.
My belief is that having a picture of author on the eCom website may make the business less "businesslike".
Thinking further from my own point of view, if I am buying something, I do not want to see the picture of an employee (or someone) next to the product I wish to buy. It just makes the site look more amateurish.
It could work well with reviews, blogs and similar, but not on home pages or product pages. This is why I have left authorship on "About us" page only - it makes more sense having it there than on the home page or product page.
Perhaps CTR may be increased if the site ranks further down the SERPs.