This is a natural process for any 'whole', where aspectual refinement leads to an increase in apparent quality. This is not something 'original' to the I Ching, it is something that is 'standard' when we deal with any 'whole'. Thus, in our brain, every new situation is coloured by emotion which then influences all of the following links to that initial moment - the concept of 'first impressions being important' stems from this neurological 'fact'. Since the 64 hexagrams are supposed to manifest 'all that is', we can assume that any change manifest in a hexagram demonstrates the influence of another hexagram, a 'transforming' influence. A step through a hexagram manifests change at work - change being in the form of the influence of another hexagram.
Every hexagram has a structural opposite that serves as an extreme.
Thus, hexagram and its opposite serve as the opposite sides of the same coin. This coin can be named, taking the user 'up' a level, but moving from a specific state to a more generic state. The nature of the description is biased to the nature of the bottom line. Hexagram 28 is found to describe the movement from hexagram 16 to hexagram 09, and in the context of line 1 of hexagram 1, hexagram 16 is biased to the line unchanging, and hexagram 09 is biased to the line changing. Thus, in the context of the whole, hexagram 28 describes the gross context.