My inspiration for the distribution of the number of days in the Easter Island calendar originated from the Mayan calendar:

5 Tzek	6 Xul	7 Yaxkin	8 Mol
9 Ch'en	10 Yax	11 Sac	12 Ceh
		200
13 Mac	14 Kankin		15 Moan
16 Pax	17 Kayab	18 Cumhu	19 Vayeb
1 Pop	2 Uo	3 Zip	4 Zotz

Each month had a glyph of its own. There were 18 months with 20 days in each, together spanning 360 days. The 19th and last of the months was special in having only 5 days.

After studying glyphs, names and other aspects (ref. mainly Gates and Kelley) I arranged the months into the pattern above, with 10 redmarked months for 'summer', and with 'winter' being divided in two equal parts by the 19th exceptional 5-day month.

200 + 80 + 5 + 80 = 365.