CVS version of texpower.sty. Minimal example:
\documentclass{foils}
\usepackage[display]{texpower}
\begin{document}
\foilhead{A page}
\begin{center}
\stepwise*{\overlays{1}{A word}}
\end{center}
\end{document}
If you replace the display option with printout "A
word" is no longer centered.
Regards, Hans