Joshua Maserow from Silverblade Computers and Electronics CC just asked me today what happened when applying 12V on the input. I replied that the device will be fine, but the device will only measure up to 10V.
Then I got home, I applied 12V on the input, and the device measured correctly! I had miscalculated the maximum range when using the minimum gain.
The Specifications have been updated, and I also added tjhe Absolute Maximum Voltage.

I have been playing around checking the frequency response of the device. Unfortunetely, the XMEGA's ADC bandwaidth is not very high.
I had set up my analog filters at 320kHz, but the signals on the Xprotolab display gets attenuated to -3dB at around 200kHz.

I have recalculated the input range and verified on a unit, the analog range is:
Analog Voltage Input Range: -14V to +20V