I thought these couldn't possibly be right and you must be including their storage and cache usage, but I'm seeing similar reported on my iPhone. Rounded to the nearest megabyte.
I'm still skeptical (or just hopeful?) that there's some storage accounting bug here, and it's including caches. I'm not in a place to plug it into Xcode right now, maybe someone else can check the actual IPAs?
edit: also, I do see Apple's own apps in mine. Music reports 39mb; Photos 791kB (lol?)
edit: also, I do see Apple's own apps in mine. Music reports 39mb; Photos 791kB (lol?)