Not all rounds are equal. He won't have a training partner with Randy's clinch skill. He'll be prepared for five rounds with the guys he happens to train with, sure. He will not be prepared for five rounds with a guy who can take his advantages away and keep him from riding them the whole time.
actually that's 80% wrong.
he'll be training with fresh guys every round in his sparing.
and where you really prepare your cardio isn't really there either. It's in your bag and HIIT training.