\documentclass[a4paper,oneside]{article}
\usepackage[left=2.5cm,top=3cm,right=2.5cm,bottom=3cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{tabularx}
\usepackage{array}
\usepackage{csvsimple}
\usepackage{etoolbox}

\newcommand{\csvext}{.csv}
\newcommand{\datafile}{\jobname\csvext}

\begin{document}
\pagestyle{empty}

\begin{center}
	\section*{Stundenliste}
\end{center}

\vspace{1cm}

%\Name ;\MonatJahr ;\IstStunden ;\SollStunden ;\DiffStunden
\csvreader[%
		separator=semicolon,
		no head,
		filter test = \ifnumless{\thecsvinputline}{2}]{\datafile}{1=\Name,2=\MonatJahr}{%

	\begin{tabular}{l l}
		Name: & \Name \\
		Monat/Jahr: & \MonatJahr
	\end{tabular}
}

\vspace{1cm}

{
%\adjustboxset{margin=3pt}
\noindent
\begin{tabularx}{\textwidth}{
	|>{\raggedleft\arraybackslash}p{2cm}%
	|>{\raggedright\arraybackslash}p{2cm}%
	|>{\raggedleft\arraybackslash}p{1.25cm}%
	|>{\raggedleft\arraybackslash}p{1.25cm}%
	|>{\raggedleft\arraybackslash}p{1.25cm}%
	|X|}
	\hline
	\centering\arraybackslash\bfseries Datum  & %
	\centering\arraybackslash\bfseries Wochentag  & %
	\centering\arraybackslash\bfseries Beginn  & %
	\centering\arraybackslash\bfseries Ende  & %
	\centering\arraybackslash\bfseries Dauer  & %
	\centering\arraybackslash\bfseries Anmerkung  %\\ \noalign{\hrule height 1.5pt}
	\csvreader[%
			separator=semicolon,
			no head,
			filter test = \ifnumgreater{\thecsvinputline}{1}]{\datafile}{1=\csvdate,2=\csvday,3=\csvstart,4=\csvend,5=\csvduration,6=\csvcomment}{%
		\\\noalign{\csviffirstrow{\hrule height 1.5pt}{\hrule height 0.5pt}}
		\csvdate & \csvday & \csvstart & \csvend & \csvduration & \csvcomment
	} 
	\csvreader[%
			separator=semicolon,
			no head,
			filter test = \ifnumless{\thecsvinputline}{2}]{\datafile}{3=\Ist,4=\Soll,5=\Diff}{%	
		\\\hline
		\multicolumn{5}{>{\tiny}p{7.5cm}}{} \\
		\multicolumn{2}{p{4cm}}{} & \multicolumn{2}{>{\raggedleft\arraybackslash}p{2.5cm}}{Ist-Stunden:} & \multicolumn{1}{>{\raggedleft\arraybackslash}p{1.25cm}}{\Ist} \\
		\multicolumn{2}{p{4cm}}{} & \multicolumn{2}{>{\raggedleft\arraybackslash}p{2.5cm}}{Soll-Stunden:} & \multicolumn{1}{>{\raggedleft\arraybackslash}p{1.25cm}}{\Soll} \\ \cline{3-5}
		\multicolumn{2}{p{4cm}}{} & \multicolumn{2}{>{\raggedleft\arraybackslash}p{2.5cm}}{Differenz:} & \multicolumn{1}{>{\raggedleft\arraybackslash}p{1.25cm}}{\Diff}
	}
\end{tabularx}
}

\end{document}