listesso tempo

[Helge]

I want to write an indication that the beat continues at a meter
change. I found in the notation manual a solution with \tempo

\version "2.18"
\relative c' {
  \time 4/4
  | c4 c c c
  \tempo \markup {
    \concat {
      \smaller \general-align #Y #DOWN \note #"4" #1
      " = "
      \smaller \general-align #Y #DOWN \note #"4" #1
    }
  }
  \time 3/4
  | c c c
  | c2.
}

Is there a simpler way to write this "listesso tempo"?

Regards
Helge