There are two basic year concepts, summer contra winter respectively sun waxing contra sun waning. In both cases it would not be strange if wishful thinking worked to find calendar solutions which prolonged summer / waxing and shortened winter / waning. For instance did Maui make the Sun move slower.

Equinoxes do not seem to play any fundamental role in the rongorongo texts and the equality of the lengths of day and night apparently is not a major concern in the calendars. Instead of a division of time in two equal parts a division in three unequal parts can be read about. And these can be connected with the path of the sun from the tropic of Cancer to the equator (24 multiples of 10 = 240) and with half the distance in degrees from the equator to the tropic of Capricorn (12 * 10 = 120). The sum is 360 which lends support to the concept of a factual year with 360 days.

Another 120 days (12 degrees) will move the sun to the lowest point in his cycle, and 360 + 120 = 480 is a measure of importance in the rongorongo texts.

The calendars of rongorongo are astronomically defined, not defined by the activities in an agricultural society.

With the path of the sun described by glyphs carrying 20 days apiece calendar II (on the Paris Snuff Box) with 24 glyphs can be translated into 20 * 24 = 480 days. Mount Meru has 84 instead of 48 as her characteristic number and we can understand why - it counts also with the reversal of the waxing of Sun. (We can compare with 63 as the reversal of 36 and 42 as the reversal of 24.) 84 = 48 + 36.

Mount Meru symbolizes the whole, both the front side and the back side. Counting it must result in 84. First there are 8 periods for the waxing sun and then there are 4 periods for the moon. 84 = 12 'weeks'.