Does the Vx- pin of AD7609 be 180° to Vx+ pin

Hi,

From the pin description table in the AD7609 data sheet:

V1- to V8- pin description: "The signal on this pin should be 180° out of phase with the corresponding Vx+ pin"

Does it mean that if the positive input is for example +2.5V, the negative should be -2.5V?

Can I connect the negative input to GND while the positive is connected to the measured voltage (like in single ended)?

Another question, which is somehow related to the first one:

The analog input range of this device is +/-10V, +/-5V. How can it be 40V p-p?

I understand the when the Vx+ is +10V and the Vx- is -10V we get +20V and when the voltage is reversed we will get -20V.

But still, it is very confusing... I expected that voltage range of differentioal +/-10V inputs will be 20V...

Thanks,

Avi