Well the whole point of an add-on system is that it simply fixes to the back of your day scope & is pre zeroed,
so No, the scope was not moved as that would effect the zero & nullify the point of using add-on.

The unit is zero eye relief, your eye is in contact with the rubber eye cup, overall length is 120mm with 10-15mm of compression to the eye cup possible, there is also a few mm of the DSA to allow for but that can vary with how the DSA fits the scope eye bell.
I've got 4 different add on set-ups & have never found the slight change to head position to be an issue, I had much more of a problem when I had a dedicated NV unit which was so tall I had to roll my head over the stock & shoot it left eye .

I found it easy to use once I read the instructions through a couple of times there are only 5 buttons in a cross pattern, dual use for long or short press but at night you only use a couple of functions so it's easy to feel for them.

In each corner of the display is an icon for battery power, IR power, digi zoom/wi-fi, laser dot.

I think the reason the first (enlarged) pic is a bit blurred is that I'd pressed the photo button several times with nothing happening (it takes a good solid press) so was getting a bit annoyed & not holding the rifle steady.