I wrote some years back about a similar error in the [blank]est-since-[blank] department, one that resulted in understatement rather than overstatement. (After searching frantically for that blog entry I knew I wrote, I finally found my rant in "The Elephants of Style.") When Roy Jones Jr. won a version of the world heavyweight boxing title at 193 pounds in 2003, USA Today called him "the lightest heavyweight champion since 205-pound Michael Spinks in the mid-1980s." Of course, 193 is lighter than 205. It's also lighter than 199 3/4, which is what Spinks weighed when he beat Larry Holmes for the title. While it is interesting that there was another example of a not-so-heavy heavyweight champ in the interim, Jones's fake title (Lennox Lewis was the real champion, but that's another rant) made him the lightest champ since 180-something-pound Floyd Patterson way back in the late '50s and early '60s.
Before we start arguing about whether since can mean because (spoiler: it can), maybe we should all get on the same page about what since means when it means "since."