I can't personally speak for the 280 or 280AI, but what your book is telling you seems to be similar to what I have heard about the 280AI.

As far as reaming your chamber out to 280AI, should be an easy task for a competent gunsmith.

I would always say in a bolt gun or single shot there is hardly any downside to going with an AI chamber over a standard one. Some calibers aren't worth it though. 308 being a great example. The biggest benefit in my mind is the increased brass life. Cuts your trimming down to almost nothing, and with some calibers the velocity gains are nice. 243, 250 Savage, 22-250, 257 Bob, and 25-06 coming to mind. I have the 243AI myself and I love it. 4000+FPS out of a 58gr V-Max and brass that seems to last forever, gotta love it.