scaling styles

\documentclass{standalone}

\usepackage{pgfplots}

\newcommand{\getpgfkey}[1]{\pgfkeysvalueof{/pgfplots/#1}}
\newcommand{\xmin}[0]{\getpgfkey{xmin}}
\newcommand{\xmax}[0]{\getpgfkey{xmax}}
\newcommand{\ymin}[0]{\getpgfkey{ymin}}
\newcommand{\ymax}[0]{\getpgfkey{ymax}}

\pgfmathsetmacro{\yminscaledDOWN}{\pgfkeysvalueof{/pgfplots/ymin}}

\usepgfplotslibrary{groupplots}
\pgfplotsset{
xscalingdown/.style={
x coord trafo/.code=\pgfmathparse{##1/(1e#1)},
every axis/.append code={%
\edef\pgfmathresult{\xmax/(1e#1)}\global\let\xmaxSCALED=\pgfmathresult
\edef\pgfmathresult{\xmin/(1e#1)}\global\let\xminSCALED=\pgfmathresult
},
xlabel style={
append after command={
node [rotate=90, anchor=base west] at (\tikzlastnode.base east) {$\cdot{10^{#1}}$}
}
}
},
xscalingup/.style={
x coord trafo/.code=\pgfmathparse{##1*(1e#1)},
every axis/.append code={%
    \edef\pgfmathresult{\xmax*(1e#1)}\global\let\xmaxSCALED=\pgfmathresult
    \edef\pgfmathresult{\xmin*(1e#1)}\global\let\xminSCALED=\pgfmathresult
},
xlabel style={
append after command={
node [rotate=90, anchor=base west] at (\tikzlastnode.base east) {$\cdot{10^{{-1}#1}}$}
}
}
},
yscalingdown/.style={
y coord trafo/.code=\pgfmathparse{##1/(1e#1)},
every axis/.append code={%
    \pgfmathparse{\ymax/(1e#1)}\global\let\ymaxSCALED=\pgfmathresult
    \pgfmathparse{\ymin/(1e#1)}\global\let\yminSCALED=\pgfmathresult
},
ylabel style={
append after command={
node [rotate=90, anchor=base west] at (\tikzlastnode.base east) {$\cdot{10^{#1}}$}
}
}
},
yscalingup/.style={
y coord trafo/.code=\pgfmathparse{##1*(1e#1)},
every axis/.append code={%
\pgfmathparse{\ymax*(1e#1)}\global\let\ymaxSCALED=\pgfmathresult
\pgfmathparse{\ymin*(1e#1)}\global\let\yminSCALED=\pgfmathresult
},
ylabel style={
append after command={
node [rotate=90, anchor=base west] at (\tikzlastnode.base east) {$\cdot{10^{{-1}#1}}$}
}
}
},
}

\begin{document}
\begin{tikzpicture}
\begin{groupplot}[
group style={
    horizontal sep=0.2cm,
    group size=2 by 1,
    ylabels at=edge left,
    yticklabels at=edge left,
},
ymin=-100, ymax=1300,
xlabel={The label for the x-axis},
ylabel={Some y-values},
xscalingdown=3,
yscalingdown=3,
]
\nextgroupplot
\addplot[only marks] coordinates{(2000,1200) (3000,500)};
\draw[ultra thick, dashed, blue] (axis cs:\xminSCALED,\yminSCALED) rectangle (axis cs:\xmaxSCALED,\ymaxSCALED);
\nextgroupplot
\addplot[only marks] coordinates{(2100,1000) (2800,1200)};
\draw[ultra thick, dashed, blue] (axis cs:\xminSCALED,\yminSCALED) rectangle (axis cs:\xmaxSCALED,\ymaxSCALED);
\end{groupplot}
\end{tikzpicture}
\end{document}