Even if there are no efficiency changes from the 16 series the Air only has a roughly 12% smaller battery than the 16 or the 16 Pro which seems to be in the ballpark for most of the battery tests we've seen (and what I've seen in my first 24 hours as well).
You guys are all making good points ...
I just think Apple brought that MagSafe battery pack back for some reason.
Maybe it was just to quell concerns.
I'm glad they brought it back no matter what!
I have a couple of them for my 13 Mini that I use occasionally.