SRX Encoder and SRX header inconsistency

[asid61]

I was wondering if anybody knows how the Talon SRX processes data.
This is a picture of the SRX Encoder output on the 10-pin header:
https://i.gyazo.com/dbc09bf7eead22a3...8055b9918c.png

This is a picture of the Talon SRX 10-pin header input:
https://i.gyazo.com/38add2e69120fccc...616ace90d2.png

The SRX encoder clearly has a PWM output on pin 9, and no analog output (the Talon analog input pin remains floating). However, the Talon SRX has the quadrature index on pin 9.
Is it simply that when you set the SRX to read from the SRX encoder in code, it automatically sets the Index pin to read PWM instead of an index pulse? Or does it track the pulse width of the Index pin as well as have an interrupt to it to effectively have both Index and PWM reading set up at the same time? Or is the Index pin not meant to read Index at all, but PWM only?

On the same note, is it possible to have both Quadrature and Absolute positioning working at the same time on the SRX encoder? Does the Index pin get used as an actual Index, ever?