I had my ride in an aircraft that both the examiner and I had a lot of experience in, so I can't really speak from my personal experience, as he only asked me cursory questions on systems and instead concentrated on other things.
From friends' experiences that did them at ATP Mill type operations (10 hour course), they were gouged up with a few minor systems questions, but it wasn't anything close to what you have. Think more big picture and less detailed. I think in the military we tend to nuke out systems a little too much down to the builder specs when we only need to know how it affects us as operators.
If in doubt, talk to your examiner and ask him what he expects in the level of detail.