Errata has to not alter the layout. Exactly for that reason.
I hadn't thought of page numbers in other books, but obviously that is an important thing.
There is an interesting example of this on page 53 of the new PDF, where compare PDF shows that the layout person subtly shrunk the line spacing between the lines on the right hand column so all the stuff would still fit on that page. I can't see it at all with my naked eye, but the thumbnail image Acrobat creates to show the difference makes it obvious.
Say what you want about the rules themselves, but much respect to Matt Heerdt (layout) and the art directors Brent Evans and James Mosingo. The book really does look great; easy to read text with clear headings, sidebars, etc. I find the border graphics a bit busy, but overall the impression is very good, and I love that purple color. They did a bang up job, I think.
When that second errata file hit his desk, there must have been places where Matt Heerdt was like "Jesus, Mary and Joseph, you want me to squeeze WHAT into that column?!" :-) I don't envy his job.