A 180 on the A&A rule. The core rules don't address it, while the core spells go the way he is going. So its not really a complete 180.
As for errata, here are the options:
A&A is correct: Change 4 spells, half in the core book.
A&A is incorrect: Change 1 spell, 2 item effects, and the note in A&A.
Overall the editing is in the same ballpark either way, about the same number of entries and across 3 books in either case. I think A&A being correct is less editing, myself. But it's not like one requires so much editing all over the place than the other. He chose he would rather have core be correct with a little bit more editing.