Inserting a command in a def causes a bug

Question

When I execute the following command, it works:

\makeatletter\CROP@center\makeatother 

But, when I include this command in a \def, as shown below, it no longer works:

\def\fixCroppingBugCausedByChangeOfGeometry
{\makeatletter\CROP@center\makeatother}

How to fix that?

Here is my MWE.

\documentclass{article}
\usepackage{geometry}
\usepackage[
  width=25truecm, height=32truecm, cam, 
  pdftex,
  center
]{crop}
\def\fixCroppingBugCausedByChangeOfGeometry
{\makeatletter\CROP@center\makeatother}
\begin{document}
Page 1
\newpage
\newgeometry{left = 5cm, right = 5cm}
\fixCroppingBugCausedByChangeOfGeometry
%\makeatletter\CROP@center\makeatother
Page 2
\newpage
\restoregeometry
\fixCroppingBugCausedByChangeOfGeometry
%\makeatletter\CROP@center\makeatother
Page 3
\end{document}

---

PS: I have to do that because I want to execute the command \CROP@center only if the crop package is loaded.