Clash between mhchem and breqn. Any way to dodge or fix?

Question

The use of breqn causes the subscript numbers in chemical expressions, formatted by mhchem, to be exlargened and perhaps moved slightly making it look ugly.

Is there a way to avoid this or should I stop using breqn?

Many thanks

MWE - comment out breqn to see the diference

\documentclass{article}
\usepackage{amsmath}
\usepackage{breqn}
\usepackage[version=3]{mhchem} 

\begin{document}
\ce{H2SO4}
\end{document}

Answer 1

\documentclass{article}
\usepackage{amsmath}
\let\xxmathchoice\mathchoice
\usepackage{breqn}
\let\yymathchoice\mathchoice

\usepackage[version=3]{mhchem} 

\begin{document}
\let\mathchoice\xxmathchoice
\ce{H2SO4}
 ...
\let\mathchoice\yymathchoice
\begin{dmath}...
\end{document}