In regards to the 13M written exam, how difficult or challenging are you making the questions?

Background: I have just proctored the most recent 13M Safety Exam. One Battery did well, while the other did poorly. This exam was based off of the last one given in the second quarter of 2015. Since we are deployed OCONUS on an FA mission I added a few questions tailored to our current mission. The difficulty of the exam was increased slightly to reflect the fact that we are training on our craft and utilizing our equipment seven days a week, which is an incredible opportunity for a Guard Unit.