auto-beaming in uncommon time signatures

[Matt Huber]

Howdy!

I'm experiencing some unusual behavior with beaming that I can't seem to
correct.    In 12/16 time, if the Score.beatlength is set to 6/16, lilypond
correctly produces two groupings of 6 notes each.  However, changing the
beatLength to 3/16 produces inconsistent beaming within a measure: 2-4-3-3
instead of 3-3-3-3.  Can someone explain why this is happening, and how to
correct this?

Thanks!
~Matt

Example code:
---------------------------------------
\version "2.10.29"

{
  \time 12/16
  #(override-auto-beam-setting '(end * * * *) 6 16 )
  #(override-auto-beam-setting '(end * * * *) 12 16 )
  #(override-auto-beam-setting '(end * * * *) 18 16 )
  #(override-auto-beam-setting '(end * * * *) 24 16 )
  \set subdivideBeams = ##t
  \set Score.beatLength = #(ly:make-moment 6 16)

  b16 b b b b b b b b b b b 
  \set Score.beatLength = #(ly:make-moment 3 16)
  b16 b b b b b b b b b b b 
}
-----------------------------------------