Quad-Rotor I or X

[FLGulf]

Am reading the manuals in preparation of my P1 quad's arrival.
http://download.dji-innovations.com/downloads/nazam-v2/en/NAZA-M_Quick_Start_Guide_v1.24_en.pdf
On page 6, there are two choices that apply to a quad:

• Quad-Rotor I - where the arms are like a cross with Motor 1 leading.
  Quad-Rotor X - where the arms are like an X with Motors 2 (left) and 1 (right) leading.

I see from the figures that the front is different, but the motors and their rotation (CW & CCW) are the same.
So why do they display both configs? Wouldn't X be the default?

 

[ElGuano]

The mode doesn't refer to the orientation of the quad (not sure if you meant it that way).

Most people choose X or Y over I because the spacing between the front blades allow for a camera to be mounted to the bottom of the frame without having a long front boom in view all the time. It also lets you hang other peripherals along the sagittal plane more easily.

 

[OI Photography]

The NAZA used in your Phantom is also used in other custom-built multirotors, some of which use alternative configurations like that

 

[FLGulf]

Makes sense. Thanks.