I actually called them about this. Here's what they told me...
Minute oats are whole oats crushed to minute oat size. In other words, they are coarsely ground. It's not that they cook any faster, it's that they cook faster because they're smaller. If a whole oat were the same size as a piece of minute oat...it would cook at the same speed. It's like taking a 30 minute steak, cutting of a tiny piece of it and calling it a 5 miniute steak, just because it would cook faster due to the size.
It would stand to reason that there would also be some loss of moisture in the grinding process, as well.