line-width in lilypond-book differs in manual vs. glossary

[Graham Percival]

Examples from the user manual with [quote, ragged-right] produce this:

\paper {
  #(define dump-extents #t)

  line-width = 160\mm - 2.0 * 0.4\in
  ragged-right = ##t
  indent = 0\mm
  force-assignment = #""
  line-width = #(- line-width (* mm  3.000000))
}

Examples from the glossary with [quote, ragged-right] produce this:
\paper {
  #(define dump-extents #t)

  line-width = 5\in - 2.0 * 0.4\in
  ragged-right = ##t
  indent = 0\mm
  force-assignment = #""
  line-width = #(- line-width (* mm  3.000000))
}


Does anybody know why, or how to fix this?  I have a slight preference 
for 160\mm, but it doesn't really matter which one we pick, just as long 
as they're the same.

I couldn't find "5\in" anywhere in Documentation/user/.  Where else 
should I look?

Cheers,
- Graham