For full disclosure, I worked at a salon in high school as a receptionist. So I'm kinda an expert in this matter. I'm practically a hair doctor.
The whole "later, rinse, repeat" is a marketing gimmick. For reals though. If your hair isn't lathering well, it's almost always because your hair isn't wet enough - not that you need more shampoo, or to "repeat".
Before you shampoo your hair, make sure it is soaking wet, and run your hands through it like you are lathering it. That will make sure your hair is soak through and will lather sufficiently.