m above beam in guitar notation

[Orm Finnendahl]

Hi,

 in the following example, the "m" is printed above the beam whereas
all other right hand fingerings are notated below the beam.  Is this
related to the larger size of the letter "m"? Can someone shed a light
on this and how this could be avoided?

--
Orm

%<-------------------------------------------------------------
\version "2.18.2"

RH = #rightHandFinger
upper = \relative c' { 
    \set fingeringOrientations = #'(left)
    \set strokeFingerOrientations = #'(up)
    \set stringNumberOrientations = #'(down)
    \override StringNumber.transparent = ##t
    
    
    
    <e-1 \2 \RH #2 >8
    <fis-3 \2 \RH #3 >
    <g-4 \2 \RH #2 >
    <a-1 \1 \RH #4 >
}

lower = \relative c {
    \set fingeringOrientations = #'(left)
    \set strokeFingerOrientations = #'(down)
    \set stringNumberOrientations = #'(up)
    \override StringNumber.transparent = ##t
    
    <e,-0 \6 \RH#1 >2
}


\new StaffGroup 
    <<
  
\new Staff {
    \clef "G_8"
    \key e \minor
    <<
      \upper \\ \lower
    >>
}

\new TabStaff
    <<
      \upper \\ \lower
    >>
    
>> 
%<-------------------------------------------------------------