Clearly the publisher wants to get the books out as early as possible, and I can understand why. The new version of iOS has been available to users for a week, and the early release versions of iOS6 have been circulating for a couple months. That means developers have an immediate need to update existing apps as well as produce new apps to support the new mobile OS.
"Developers can't wait for the right answers, especially from amazing teachers and trainers like Erica Sadun, Stephen Kochan, and Robert Clair," said Paul Boger, Publisher of Pearson Technology Group. "We want our customers to gain expertise as soon as the experts do. With Early Editions, they can."
On the other hand, this is the publishing industry, and I can easily see this Early Edition concept eventually losing the extra work that Pearson now plans to do after the early sales. After all, if developers are willing to put up with the crappy edition then why bother fixing it? Some bean counter could decide that the funds are better spent on the later editions of the book - the ones sold under a different ISBN.