롱타부 하단 캡션이 너무 가깝습니다.

Question

테이블 하단에 롱타부 캡션을 추가하고 싶습니다. 나는 이것이 좋지 않다는 것을 안다. 그런데 그렇게 하라고 했어요. 코드 샘플처럼 하면 캡션이 표에 너무 가까워집니다. 그런데 캡션 뒤에 세로로 큰 공간이 있습니다.

\captionsetup[longtable]{skip=10pt}도 사용했습니다. 도움이 되지 않습니다.

\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}