not familar with that procedure. I always recommend using the heavy guage plastic liner. I like it because I have never had any trouble with that leaking. I take it up about three feet up all walls then staple it to the studs at that point, Rock or cementious board up the walls over this. Then lay the mortar over this making a bowl shape then tile over this.
I have never heard of the other method. Remember, the best way is not the cheapest route because a leak in the pan requires all to come up and start over. Get a good reputable person and do a reference check.