In the faq you don't have a shot at the back arc anyways because it is out of your front fire arc. So is the Rules Reference on page 7 right or the FAQ right? To me the FAQ is wrong because that is not the closest point of the defending rear hull zone it is just closest point to closest point of the attacking arc to the closest point of the base of the defending ship. It is not the closest point of the defending hull zone.
They added the FAQ rule we're discussing because in that FAQ example, it can be argued that a part of the back hull of the VSD is in fact in the front arc of the cr90. They're measuring the closest point of the defending hull zone WITHIN the firing arc, and saying the shot is invalid because that measurement crosses a hull line.
It would have been much simpler and nonbreaking to say that the back hull isn't in the arc because the base edge isn't in the arc and call it a day.
I'm not sure if that answers your question.
Edited by Gowtah