Changing the ossia staff distance to another staff

[Menu Jacques]

Hello folks,

In the example below, how can the ossia be brought closer to the upper staff 
while keeping the same distance between the two regular staves?

Thanks for your help!

JM


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\version "2.19.80"

\new PianoStaff <<
  \new Staff = "up" \relative {
    c''4 b d c
    <<
      { c4 b d c }
      
      \new Staff \with { % the ossia
        \remove "Time_signature_engraver"
        alignAboveContext = #"up"
        \magnifyStaff #2/3
        firstClef = ##f

      }
      { e4 d f e }
    >>
    c4 b c2
  }
  
  \new Staff = "down" \relative {
    c''4 b d c |
    c4 b d c |
    c4 b d c |
  }
  
>>