I also find it hard to believe, especially since they probably have hired some of the best engineers in the world. That leads me to believe that they've been gaming the numbers this entire time, and now it is biting them in the ass, as Gruber put it.
Particularly since, despite their claims in their press release, Apple's first-gen iPhone (or at least my first-gen iPhone) calculates bars very differently. Based on using field test over several days an observing signal strength and bars displayed, I put together this spreadsheet.