I am an Editvoicepack user. I ran it when I first installed FS9 because I sometimes use the default ATC. I also, accelerated the voices and this causes a problem with PFE. Since, PFE only copy what the default ATC says to AI planes, this means PFE will get overloaded and you will see planes moving into the runway before getting the clearance by tower controller. So, I ran Editvoicepack again but this time without the voice acceleration and pumped up the default ATC volume in FS and now PFE gives instructions faster the the default ATC.
Cheers