I might be misunderstanding this chart, but it appears the author is saying that by enrolling for the minimum number of credits, you will receive the associated insurance for free. For at least one university listed -- Penn State -- that is not true. You must also purchase the insurance plan.
OK, I did misunderstand. The numbers make more sense now. I believe step 3 "enroll, get that cheap insurance" should make this a little more clear. (It's not just the act of enrollment that gets you the insurance.)