Hmmm- is it something that would be apparent to the semi-trained eye? I've used Sigil to fix typos, create better TOCs, and light work like that. As far as fonts go, I did look for that but there were only 4 .ttf files in the Font folder when I looked in Sigil.
Anything else I could look for? I should point out that I've got probably 6 or 8 examples of this- in books that I would not otherwise question the quality. I was wondering if it was something inherent in the ADE.