@contents up-to-date at start

[Kevin Ryde]

The "Contents" node of the texinfo manual talks about putting
@contents at the end of a document to ensure it's always up to date.

I tried, in a highly unscientific fashion, adding an @page to a
document, and on re-running texi2dvi the contents at the start seemed
to have updated correctly.  Is it only in certain circumstances that
there's a problem?  Or does texi2dvi use some magic to keep it right.