We have earlier (in the tara 'chapter') observed how an obliquely cut off bottom end of  henua is used at the final of the calendar in K (and in the last text line on side b of A):

 

29

Kb4-10

Kb4-11

Kb4-12

Kb4-13

Kb4-14

Ab8-64

Ab8-83

In addition, there is a henua in the K calendar cut of obliquely at the top:

14
Kb1-2 Kb1-3

The location of Kb1-3 in the calendar implies 'cut off at the top' (when sun stands high) means 'end' of the 1st half year, while 'cut off at the bottom' refers to the 2nd half year. Although we have very few glyphs of this general type to rely on, it is plausible to add Eb4-19 to the group:

13
Eb4-13 Eb4-14 Eb4-15 Eb4-16 Eb4-17
Eb4-18 Eb4-19 Eb4-20 Eb4-21

The bottom end is sloping slightly downwards, maybe indicating how the course of the sun beyond its maximum at Eb4-18 now is sloping downwards. The 13th period of the 24 in the Keiti calendar is a kind of confirmation (as well as ordinal number 19 - 'sun finish').

A more thorough examination of the cut off ends of henua glyphs will have to wait until later on, though.