why Phusion polymerase is not recommended for overlap PCR? - (Feb/15/2012 )

According to this protocol it is not recommended to use Phusion polymerase in overlap PCR reactions (4.2), Why?

http://openwetware.org/wiki/PCR_Overlap_Extension

Not sure why they say that, a previous PhD student in our lab used Phusion for her SOE PCR and it worked just fine.