[Tex/LaTex] Sub caption of table produces large white gap

Question

For tables I need a caption above, and sub captions beneath the table, to define all abbreviations used in the tables.

The solution I'm using so far results in a large white space after the table/ the tables' sub caption.
I want to emphasize that just the sub caption leads to this gap. Inserting the table without the sub caption shows a typical beautiful LaTeX table and text surrounding it normally.

Does anyone have an idea on how to reduce this space/ gap?

I append the code I'm using and an image so you can see the gap.

Thanks a lot for any help/ advise.

\documentclass[captions=tableheading]{scrbook}

\usepackage{booktabs}
\usepackage{array}

\begin{document}

some text ...

\begin{table}[h]
\centering
\captionsetup{singlelinecheck=off}
\caption
[table heading]
{more specific table heading.}
  % Table generated by Excel2LaTeX
  \begin{tabular}{l}
  \toprule
  some entry \\
  \midrule
  some other entry \\
  \bottomrule
  \end{tabular}%
\\[0.35cm]%subcaption
\caption*{
explanations of entries
}%
\label{tab:cleaning_solutions}
\end{table}

some other text ...

\end{document}

Answer 1

Here is a suggestion that locally uses \captionbelow instead \caption.

\documentclass[captions=tableheading]{scrbook}

\usepackage{booktabs}
\usepackage{array}
\usepackage{caption}% <- needed for \caption*

\newcommand\addcaptionbelow[1]{{%
  \let\caption\captionbelow
  \caption*{#1}%
}}

\usepackage{blindtext}% dummy text
\begin{document}
\blindtext

\begin{table}[htb]
  \centering
  \captionsetup{singlelinecheck=off}
  \caption
    [table heading]
    {more specific table heading.}
  \begin{tabular}{p{.9\linewidth}}% Table generated by Excel2LaTeX
    \toprule
    some entry \\
    \midrule
    some other entry \\
    \bottomrule
  \end{tabular}
  \addcaptionbelow{explanations of entries}
  \label{tab:cleaning_solutions}
\end{table}

\blindtext
\end{document}