Lots of people have read this thread, but as yet no comment from the magazine.
I notice this with lots of posts in this section - readers go to the trouble of asking a question, but no-one from the magazine seems interested enough to answer. Whilst I appreciate that publishing a magazine is probably a full-time job, I would question the desirability of having a Feedback Forum if no-one from the magazine has the time to reply.
Thanks for taking the time to post your question, and sorry that it's taken so long for you to receive a reply.
I've had another look at the test images and to my eye they don't look particularly over-exposed. There is one image image which does appear lighter than the others, although that was captured using the IXUS's 'Auto HDR' mode and is captioned to that effect.
If you'd like to discuss the matter further feel free to drop me an email (firstname.lastname@example.org), and sorry once again for the slow reply on the matter.