You may want to raise a hairy eyebrow to your OW instructor. He need not beat the issue to death, but I would expect them to mention DAN in more than just passing.
This is perhaps one of the highlights of a low quality instructor vs a good one. In my opinion.
Just plain silly.
a.) Instructors mention a hundred things that students don't retain. I had a student for a refresher last night who insisted they were never told in their OW class to "blow bubbles" when the reg was out of their mouth. I know their instructor, and I know that just ain't the case.
b.) If the instructor mentioned it ONE too many times, someone would be on here whining that the shop/instructor was trying to up sell them constantly.