The periods of G and K move in parallel up to number 15:

15
Ga4-23 Ga4-24 Ga4-25 Ga4-26 Ga4-27
15
Kb1-4 Kb1-5 Kb1-6

Then they diverge in the 16th period, which is short in G but very long in K:

16
Ga5-1 Ga5-2 Ga5-3
16
Kb1-7 Kb1-8 Kb1-9 Kb1-10 Kb1-11
Kb1-12 Kb1-13 Kb1-14 Kb1-15 Kb1-16
... ...
*Kb1-17 *Kb1-18 *Kb1-19
*Kb1-20 *Kb1-21 *Kb1-22

Manu kake ought to indicate the beginning of a new season and we have just turned the tablet from side a to side b. The 7th glyph on side b is a point of major change:

 
Gb1-6 Gb1-7 Kb1-6 Kb1-7

We have thus 'proven' that the 16th period in K is connected with a radical change. Number 16 is a number connected with 'final', and if we add 4 we reach 20 (as we have learned from the Hawaiian Moon calendar).

Henua in Kb1-6 (where 1-6 alludes to 16) is drawn with an open top, i.e. it could mean there are only 28 'real' periods in the K text. There are no more such 'open' henua glyphs in K.

However, the primary idea was probably to show how the head of kiore is gone ('the ripe fruit has fallen').