It is good to hear that you passed the exam keeflyer, and your advice regarding using the examples and material on the graphs is absolutely correct.
But this stuff should be the absolute starting point in the lessons provided by any performance instructor. Any instructor who fails to emphasis the value and importance of the examples and information on the graphs, does not deserve to be called a performance instructor. When I instructed this stuff the lessons included a full examination of each graph, followed by 6 or 8 practice questions, all of which were the fully debriefed. The student might complain that the work rate was exhausting, but they could not complain that they had not been fully prepared for the exams.