What I have been calling the Giza Grid cycle of 99 Lunar months is actually known by a different name than the Metonic cycle called the Octaeteris cycle as mentioned in this Wiki article:
This cycle of the Moon has been known for countless millennia by many ancient cultures as the article states, and was utilized by the Greeks to compute the Olympic games among other events. And even though both the integer count of this cycle into 99 mos of 29.53125 days is imprecise, as well as the Sothic 4 Year cycle of 1461 days, there does appear to be an adjustment ratio factor which brings this cycle extremely close to the current know value of the Lunar Synodic cycle of 29.5306 days. This ratio is 1837/1836. Now I have been examining the divisor of this ratio 1836, in a few contexts already as it is a multiple / 32 = 57.375 Radian SOL, calculation. But in this application, I shall demonstrate how this particular ratio brings both inaccuracies of the Lunar and Solar cycles of the Egyptian acct. system into precision. Starting with the basics, 99 x 29.53125 day LM, / 365.25 JY = 8.00436345 Yrs. This figure is in excess of an integer number of JY, by the close ratio x 1836/1837 = 8.00006148 JY. Then using this value multiplied by not the Julian, but the more precise Gregorian Calendar cycle 365.2425 days. = 2921.942245 day Octaeteris cycle. Such that when I divide this value by 99 Lunar Months = 29.51456814 days, I get a diminished value of the Lunar Month. But when I then multiply this figure by the aforesaid 1837/1836 ratio, I get 29.53064361 days. Synodic Month. Well, don't that beat all including my former precision calculation of the Luni/Solar cycle using the cube rt. 1892 value I posted previously in the subtopic heading Lunar Target Practice. This being a mere 4.63 seconds off the modern value.