Well, the truth is that they do sound different to me even after they have been altered to sound the same.
The PJ agent or whatever sounds like she talks more in her teeth or something than "Fayla".

It's hard to explain, but I don't hear the two voices coming from the same person.

They sound like their skull anatomy and the origin of the voices(nasal or gutteral) are slightly but nevertheless different.
It's just what I hear, I'm going to wait and see though before I form an opinion.