One way of looking at the three centers, which fits nicely in with Buddhism and other traditions, is through Ground awakening and skillful means.
The head center awakening, when it is full, is Ground awakening. Awake void awaking to itself, as awake void and form, inherently absent of any I with an Other.
And the heart and belly awakenings, the loving and felt-sense of all as Spirit, is part of the skillful means, how this Ground awakening is expressed in the world through this particular human self.
Before head center awakening, the heart and belly awakenings makes the shift into Ground awakening a little more likely, and also makes it easier to be who we take ourselves to be. After a Ground awakening, they become part of the skillful means in how it is expressed in the world. In either case, it is part of the unfolding evolution of the form aspect of God.