Round A4 up to a multiple of 4 total pages. I can't easily get the number of actual pages processed, so rely on telling the (rather hacky, and surprising - I have to divide to a separate counter to force an integer result) macro the number of pages used before the current numbering started.

\needspace{5\baselineskip}
\section{@SECTIONNAME@ tunes}

{\renewcommand{\arraystretch}{2.5}
\setlength\LTleft{0pt}
\setlength\LTright{\fill}
\begin{longtable}{@{}>{\raggedright\arraybackslash}m{0.2\textwidth}r@{}}
\input{@SECTION@-firstlines.tex}
\end{longtable}
}