I will deal briefly here with the features of Band 4.
Basically, as this properly is of a nondual nature, the discrete identification of the 3 levels, designated here, ultimately lose any meaning. So properly it represents the integral extreme with respect to development, where both "higher" and "lower" levels are harmonised in two-way heterarchical terms (within levels), two-way holarchical terms (between levels) and ultimately both simultaneously in four-way heterarchical and holarchical terms (within and between levels).
However as such continuous integration can only be approximated in a relative manner with some degree of phenomenal rigidity remaining, there is therefore a limited sense in which a degree of differentiation can still be applied to these levels in a discrete manner.
So Band 4 (Level 1) is associated with the transcendent extreme of contemplative type development, whereby the nondual spiritual nature of reality (as beyond all phenomenal form) is attained.
However when this transcendent aspect is not fully complemented by the corresponding immanent aspect of spirit (as existing prior to all form), it thereby can become associated with a subtle involuntary negative attachment to form (in a superior sense) where one adopts an unduly otherworldly attitude to everyday involvement in affairs. This also will be coupled by a corresponding involuntary positive attachment to form (in an inferior sense) where one remains, to a degree, the victim of the instinctive physical promptings (of the "lower" self).
Level 2 is thereby associated with the passive withdrawal of identification with the (mere) transcendent aspect of nondual attainment. Then as the involuntary negative attachment to remaining form is thereby gradually eroded, equally at the instinctive level, involuntary physical promptings are likewise gradually eroded.
This then culminates at Level 3 in a more balanced nondual spiritual attainment. Now, one can simultaneously reconcile both transcendent and immanent aspects, whereby formless spirit is seen as both the goal of all phenomenal evolution and equally as the original source of that same evolution. It this way, reality is experienced as the continual present moment that is an eternity, and alternatively as an eternity that is but the immediate present moment!
However in my own case, I was soon to come to the realisation that this nondual emphasis is itself unbalanced. Therefore paradoxically, for full realisation of the nondual aspect (in absolute terms), equal attention must be given to the dual aspect (in relative terms).
So truly, with the more advanced stages, attention now increasingly switches to the manner in which both dual and nondual aspects of experience can interpenetrate in a successful manner with each other.
So I would now see the task of Band 4 (in specialised attainment of an integral nondual extreme) as the complementary side of the task of Band 2 (in specialised attainment of a differentiated dualistic extreme).
Therefore properly both of these tasks are dependent on the task of Band 6 (and in a qualified sense Band 7) in the balanced attainment in relative terms of both the integral and differentiated extremes.
Thus the wonderful thing about development, which initially one may view with a degree of frustration, is that the most complete fulfilment (that is always approximate) of any stage of development, is intimately dependent on corresponding fulfilment with respect to all stages. So development is in truth always an ongoing process, where we never fully reach our final destination and yet where the ongoing journey is vital so as to better clarify those places through which we have already passed.
Band 5 in many ways is similar to Band 3. However whereas on the outgoing journey though the three Levels of Band 3, the dualistic element (reflecting residual phenomenal attachment) is continually eroded, thus enabling the nondual aspect to clearly emerge, on the homecoming journey this dualistic element is now once again restored (in a non-attached manner).
With Band 5 (Level 1) the dualistic element is restored to the diagonal polarities, which now can operate more successfully with respect to both a complementary nondual and - relatively - separate dual polarities.
Again though this Level does have a certain discrete identity, the emphasis is still largely on the complementary links both with the earlier expression of this level (in Band 3) and its corresponding vertical links with Level 1 (Band 1).
However the emergence of the discrete differentiated aspect also helps to establish links with Level 3 (Band 2) and Level 1 (Band 6).
With Band 5 (Level 2) the dualistic element is restored to the vertical polarities, which again can now operate more successfully with respect to both complementary nondual and separate dual polarities.
Though again it has a certain discrete identity in a differentiated manner, the emphasis is still mainly on continuous integral links with Bands 3 and 1 respectively.
However, insofar as the differentiated aspect is involved, this increases the connection with Level 2 of both Bands 2 and in diminished form Band 6.
Finally with Band 5 (Level 3) the dualistic element is restored also to the horizontal polarities.
So with all this preliminary work concluded, the stage is set for the combined mature specialisation of both linear (dual) and circular (nondual) polarities in the fullest expression of both differentiated and integrated development respectively.