I have this table that I want to align the numbers based on their decimal place while the numbers are still centered. I tried to siunitx package but it didn't work :(

Any help is highly appreciated! (Data is not real)

```
\usepackage[format=plain,
            labelfont=it,
            textfont=it]{caption}
\usepackage{array}
\usepackage{siunitx}
\usepackage{booktabs}
\usepackage{multicol}
\usepackage{multirow}
\usepackage{tabu}
\usepackage{booktabs}
\usepackage[tableposition=top]{caption}

\begin{document}

\begin{table}[hbt!]
    \centering
    \caption{Time measurements for oil samples with different weights of additive X for 40 and 60$^\circ C$. Dynamic viscosity is then calculated using the viscometer constant, $C$.}
    \begin{tabular}[t]{c c c c c c}
    \toprule
         Concentration (wt\%) & $T$ ($^\circ$C) & \multicolumn{3}{c}{$t$ ($s$, $\pm1$)} & Dynamic Viscosity ($cP$, $\pm0.1$)\\
          & & 1$^{\text{st}}$ & 2$^{\text{nd}}$ & 3$^{\text{rd}}$ & \\
        \midrule
        \multirow{2}{*}{0}& 40 & 10 & 10 & 10 & 68.3 \\
           & 60 & 10 & 10 & 10 & 4.3 \\ \\

        \multirow{2}{*}{1.875}& 40 & 10 & 10 & 10 & 42.3\\
           & 60 & 10 & 10 & 10 & 3.2\\ \\

        \multirow{2}{*}{2.5}& 40 & 10 & 10 & 10 & 31.4\\
           & 60 & 10 & 10 & 10 & 4.9\\ \\

        \multirow{2}{*}{5}& 40 & 10 & 10 & 10 & 12.2\\
           & 60 & 10 & 10 & 10 & 13.0\\ \\

        \multirow{2}{*}{7}& 40 & 10 & 10 & 10 & 43.2\\
           & 60 & 10 & 10 & 10 & 1.0\\
        \bottomrule

    \end{tabular}
    \label{tab:my_label}
\end{table} ```

```