I wouldn't want to speculate on the reasons. We all have different backgrounds and the HR department has there various reasons for who they hire.

When I went through 3 years ago we only had 1 type ride bust. Re check without issue.

Having said that though we all found that it was a self study course. During the 2d week we started to schedule groups to meet and study the material together. We rotated members through each group so we got various points of view and ideas spread evenly through the class. Coming from the military I didn't have a clue as to what acronym went with which book or which one to start reading first. The 2d week we had a great instructor who finally told us what to study each night for review the next day and that's when it started to click for many of us. Otherwise it was basically...here are the books learn how to build me a 747 from matchsticks and legos. That was 3 years ago but it doesn't sound like much has changed.