status of new vertical spacing in 2.13.44

[Paul Scott]

Hi,

Should the following code work?  Am I misunderstanding 
staff-staff-spacing.  Changing the numbers doesn't seem to change the 
spacing.  (I haven't tried it in any other version).

TIA,

Paul Scott

\version "2.13.44"

\header{ poet = \markup{ staff-staff-spacing test } }

\score{
<<
    \new Staff \with {
      \override VerticalAxisGroup #'staff-staff-spacing =
       #'((basic-distance . 8)
         (minimum-distance . 7)
         (padding . 8))
    }
<< { \repeat unfold 200 a'1 } >>
    \addlyrics { \lyricmode{ what } }
    \addlyrics { \lyricmode{ why } }
>>
}