Kor Whitening/Deep Bleaching: Max Vs. Max Ultra?

If I understand correctly, there are two types of in-office KoR whitening: the max and the max ultra. The difference between the two is that the max ultra uses an extra 13% hydremide peroxide at the beginning, and also a longer period of time with KoR Night. Is the Max Ultra reserved only for recalcitrant and difficult cases or can it be used for anyone? Also, is the conditioning appointment prior to the application of the whitening gel optional or necessary?