Profiling - xref needs two-pass

Hi,

 

Docbook XSL:  The Complete Guide says that if you are
using <xref>s you need to use two pass processing to implement profiling.

 

I have just used profiling for the first time by calling the
profile-docbook.xsl stylesheet from my customisation layer.  This seems to
work and my <xref>s seem to work OK.  Am I misunderstanding?

 

Tim