Beth:
I don't do this particular rotation, but I know both videos and do combine leg training on cardio days and what I would say is that I would never do Imax 2 after PLB or any other leg workout. One reason is that I feel such a high after Imax 2, I never feel the need to do anything else after it, it is enough. Secondly, my body gets too tired with weights work to have any energy left for cardio afterwards, and even if I force myself to do it, it's not pleasurable. On the other hand, cardio first (a different cardio, a CTX cardio, not Imax 2) warms the body up and after a 5 minute rest, I can indeed do a leg weights work out afterwards and complete it with good form.
Others will tell you that for them it's more effective or more comfortable the other way around. There are different arguments here: some say that you make more strength gains if you do the weights work first, then the cardio, and that might be true. But it's definitely more comfortable the other way around. So I would say to you, what matters most to you: max strength gains, or max cardiovascular benefits and a comfortable cardio workout?
I believe the answer to your question may well be that in probably doesn't make much difference: go with whatever order feels most comfortable to your body and most right for you.
Clare