A question about NEX-6's Hybrid AF

I have a question about the NEX-6.

The Handbook says, at page 82:

If the Phase Detection AF ranging points are displayed inside the selected auto focus area, the camera focuses using the Phase Detection AF and the contrast AF in combination. You can set the display of the Phase Detection AF ranging points by selecting MENU -> [Setup] -> [Phase Detection AF Area] (page 131).

It seems therefore that, in order for the PDAF to work, it is mandatory to show its points in the display. But then, at page 131, the Handbook says:

Phase Detection AF Area Sets whether or not to display the Phase Detection AF ranging points on the screen. MENU > [Setup] > [Phase Detection AF Area] > desired mode. On: The Phase Detection AF ranging points are displayed. Off: The Phase Detection AF ranging points are not displayed. 

Here, as anybody can see, the Handbook is only talking about “showing or not” the PDAF points, and I’m not sure I’m getting this.
In other words: if I disable that option (so that I won’t see anymore the PDAF points in the Display), which of the following statement is true?

a) the PDAF is not working at all
b) the PDAF is working but its ranging points are not being shown in the display

Thanks