Longtabu, untere Beschriftung zu nah

Question

Ich möchte die Longtabu-Überschrift unten in der Tabelle hinzufügen. Ich weiß, dass das nicht gut ist. Aber mir wurde gesagt, dass ich das tun soll. Wenn ich es wie im Codebeispiel mache, kommt die Überschrift zu nah an die Tabelle. Aber nach der Überschrift bleibt ein großer vertikaler Abstand.

Ich habe auch \captionsetup[longtable]{skip=10pt} verwendet. Es hilft nicht.

\documentclass[a4paper,12pt, oneside]{book}

%tweek font spacing for better look
\usepackage{microtype}

%enable linespacing commands%
\usepackage{setspace}

%enable H option that prevent figure floats
\usepackage{float}

%used to import graphics%
\usepackage{graphicx}

%used for referencing%
\usepackage{harvard}

%customise chapter styles%
\usepackage{titlesec}

%set margins%
\usepackage[left=2.8cm,right=2.8cm,top=2.8cm,bottom=2.8cm]{geometry}

%allows to create tables with different column widths%
\usepackage{tabularx}

%allows to create tables that can span across pages%
\usepackage{longtable}%dependency of longtabu (bug fix patch applied)
\usepackage{tabu}%contains longtabu

%enable table row colors
\usepackage{color, colortbl}
%\usepackage[table]{xcolor}

%enable listing customizations
\usepackage{listings}

%enable pyglist code blocks
\usepackage{verbments}

%enables itemize space customization options
\usepackage{enumitem}

%enable caption customizations ie:\captionsetup
\usepackage{caption}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newenvironment{stablecell}{
\begin{minipage}{\linewidth-1pt}
\vspace{2mm}
}{
\vspace{1mm}
\end{minipage}
}

\newenvironment{spackenum}{
\begin{enumerate}[noitemsep,topsep=0pt,parsep=0pt,partopsep=0pt,leftmargin=*]
}{
\end{enumerate} 
}

\newenvironment{spackitems}{
\begin{itemize}[noitemsep,topsep=0pt,parsep=0pt,partopsep=0pt,leftmargin=*]
}{
\end{itemize} 
}

\newenvironment{snomargitems}{
\begin{itemize}[leftmargin=*]
}{
\end{itemize}
}

\newenvironment{scode}{\captionsetup{type=listing}}{}

\newcommand{\shrule}{\vspace{1mm}\hrule\vspace{2mm}}

%========================================

\newcommand{\cgui}{\textit{CGui}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\definecolor{gray}{gray}{0.9}

%keep only the page number%
\pagestyle{plain}

%set onehalf line spacing
\onehalfspacing

%customise chapter styles from titlesec%
\titleformat{\chapter}{}{}{0em}{\bf\LARGE}

%set bibliography listing style to agsm%
\bibliographystyle{agsm}

%monospace font in listing
\lstset{basicstyle=\ttfamily\small,
captionpos=b,tabsize=4}

\captionsetup[longtable]{skip=10pt}

\begin{document}




%%%%%%%%%%%%%%%% Table Start %%%%%%%%%%%%%%%%%%%%
\begin{longtabu} to \textwidth { |>{\columncolor{gray}}X[1, l] | X[4 , l ]| }
%%%%%%%%%%%%%%%% Heading Start %%%%%%%%%%%%%%%%%%
\hline
\endfirsthead
%==============================================
%Next page headings
\hline
\endhead
%==============================================
%Before page break text
%\multicolumn{2}{r}{Continued on next page} \\
\endfoot
%==============================================
\hline
\caption[xxxx xxx xxx xxx xxxx xxxxxxx xxxxx xxxx xxxxx]
{xxxx xxx xxx xxx xxxx xxxxxxx xxxxx xxxx xxxxx}
\label{table:xxxx_xxx_xxxx}\\
\endlastfoot
%%%%%%%%%%%%%%%% Heading End %%%%%%%%%%%%%%%%%%
%\hline
\textbf{xxxxxxxxx}
& xxxx xxx xxx xxx xxxx xxxxxxx x xxx xxxx xxxxxxx xxxxx xxxx xxx xxxxx xxxx xxxxx \\
%==============================================
\hline
\textbf{xxxxxxxxx}
& xxxx xxx xxx xxx xxxx xxxxxxx x xxx xxxx xxxxxxx xxxxx xxxx xxx xxxxx xxxx xxxxx \\
%%%%%%%%%%%%%%%%% Body End %%%%%%%%%%%%%%%%%%%%
\end{longtabu}
%%%%%%%%%%%%%%%% Table End %%%%%%%%%%%%%%%%%%%%
\paragraph{}
xxxxx xxxx xxxx xxxxx xxxx xxxxx xxxx xxxx


\end{document}