You should do the math again.
There are 29.5306 days between two full moons. That makes 369.1325 days in a year, if you calculate 12.5 moons.
In 1 year, there are 365.242 days
In 9 years, there are 3287.178 days.
In 27 years, there are 9861.534 days
If you take 12.5 moons for a year, you have...