\magnifyMusic stem-length enigma

[Mark Polesky]

Can anyone help me solve this?
Why do these two beam groups have different stem lengths?
I prefer the second one, but I have no idea how to get the
first one to look like that.

\version "2.19.9"

\relative c'' {
  \magnifyMusic 0.5 {
    c32[ c d d] d[ d c c]
  }
}

Here's the current definition of \magnifyMusic:

magnifyMusic =
#(define-music-function (parser location mag mus) (number? ly:music?)
   (_i "Magnify the notation of @var{mus} without changing the
staff-size, using @var{mag} as a size factor.  Stems, beams, and
horizontal spacing are adjusted automatically.")
   #{
     \set fontSize = #(magnification->font-size mag)
     % gives beam-thickness=0.48 when mag=1 (like default),
     % gives beam-thickness=0.35 when mag=0.63 (like CueVoice)
     \temporary \override Beam.beam-thickness = #(+ 119/925 (* mag 13/37))
     \temporary \override Beam.length-fraction = #mag
     \temporary \override Stem.length-fraction = #mag
     \temporary \override Stem.thickness = #(* 1.3 (max 1 mag))
     \temporary \override Score.SpacingSpanner.spacing-increment = #(* 1.2
mag)
     #mus
     \set fontSize = 0
     \revert Beam.beam-thickness
     \revert Beam.length-fraction
     \revert Stem.length-fraction
     \revert Stem.thickness
     \revert Score.SpacingSpanner.spacing-increment
   #})

Thanks.
- Mark

magnifyMusic-stem-lengths.png
Description: PNG image