The ua glyph type seems to be associated with the arrival of the season when sun no longer is high in the sky. In the K calendar, for instance, the only ua glyph is the last glyph in what probably was regarded as the summer half of the year:

108 glyphs for summer was chosen because the winter half of the year then would have 24 + 10 + 50 = 84 glyphs. A balance between the two halves of the year can therefore be expressed by 6 * 18 (summer) and 6 * 14 (winter).

18 is a natural choice for summer, a short expression for 180 days, and 14 will be the corresponding expression for a fortnight when moon stands high in the sky.

The parallel ua glyph in E is located 3 * 18 = 54 glyphs from the middle of the calendar, but then follows only 21 glyphs up to the end. Instead of 192 this E calendar has a total of 150 glyphs. Instead of 108 + 84 the pattern is 108 + 42 (half 84). Instead of 18 and 14 there is 18 and 7. But also in E ua is positioned as the end of the 3rd quarter.