# Problem with table spacing when aligning by decimal point?

Please see attached MWE and pdf. The problem seems to be with the column 'Test 1'? Any suggestions would be very much appreciated, I have tried altering each variable but I cannot work out where the problem is. Many thanks in advance.

\documentclass[12pt, oneside]{article}
\usepackage{graphicx}
\usepackage{gensymb}
\usepackage{amsmath}
\graphicspath{ {paperfigures/} }
\usepackage[font={footnotesize}, margin=2cm]{caption}
\usepackage{siunitx}
\usepackage{multirow}
\begin{document}
\begin{table}

\centering
\caption{clear test}
\label{tab:cleart}
\sisetup{output-decimal-marker = {\cdot}}
\begin{tabular}{|l|l|S[table-format = 3]<{\si{}}
|*{4}{S[table-format = 3.1,
separate-uncertainty,
table-figures-uncertainty=1]|}}
\cline{3-6}
\multicolumn{2}{c|}{}
&   \multicolumn{4}{c|}{\textbf{Intensity
(mV)}}                                                            \\
\hline
\textbf{Angle}
&   \multicolumn{1}{c|}{\textbf{Height}}
&   \textbf{Test 1}
&   \textbf{Test 2}
&   \textbf{Test 3}
& \textbf{Mean}   \\ \hline
\multirow{3}{*}{5\degree}
& Top    & 2.3 \pm 2.0 & 5.8 \pm 2.0 & 8.2 \pm 2.0   &
\\ \cline{2-6}
& Middle  & 3.7 \pm 2.0 & 2.9 \pm 2.0 & 26.1 \pm 2.1  &
\\ \cline{2-6}
& Bottom & 12.8\pm 2.0 & 4.5 \pm 2.0 & 13.6 \pm 2.0    &
\\ \hline
\multirow{3}{*}{10\degree}
&  Top  & 10.4\pm 2.0 & 8.8 \pm 2.0 & 11.4 \pm 2.0  &
\\ \cline{2-6}
& Middle  & 12.5\pm 2.0 & 8.0 \pm 2.0 & 7.2 \pm 2.0  &
\\ \cline{2-6}
& Bottom  & 5.3 \pm 2.0 & 2.9 \pm 2.0 & 5.1 \pm 2.0   &
\\ \hline
\multirow{3}{*}{15\degree}
& Top   & 9.6 \pm 2.0 & 6.9 \pm 2.0 & 11.0 \pm 2.0      &
\\ \cline{2-6}
& Middle  & 12.2\pm 2.0 & 9.0 \pm 2.0 & 3.5 \pm 2.0  &
\\ \cline{2-6}
& Bottom  & 2.3 \pm 2.0 & 2.2 \pm 2.0 & 1.5 \pm 2.0   &
\\ \hline
\end{tabular}
\end{table}

\end{document}


The result with S[table-format = 2.1(2)] as column specification for the third columm:
• @referencingstressesmeout The options for the S column of the third column differs from the options of the S columns of the next four columns. BTW, there are seven column specifications, but only six columns are used. Maybe the third column specification is a left-over from previous trials and should be removed. – Heiko Oberdiek Apr 11 '16 at 15:51