I had a slight nagging feeling about this. A couple years back I calculated the most and least probable dates for Easter, on the Gregorian calendar, using the current computus. That essay’s here, with results about how often we can expect Easter and when. It also holds some thoughts about whether the probable dates of Easter are even a thing that can be meaningfully calculated. And it turns out, uncharacteristically, that I forgot to do a follow-up calculating the dates of Easter on the Julian calendar. Maybe I’ll get to it yet.
nebusresearch 
I take it that the uncertainty lies in the non-predictable forces of precession, e.g., the sloshing of Jupiter’s core..
LikeLike
In the long term, over millions of years, yeah, things like that are going to come into play. I don’t know of a complete roster of the forces that affect the Moon’s orbit, and their comparative importance, though.
And I realize now that while I know of the Paschal moon, the simplified version of the moon’s behavior, I don’t know just how what goes into its approximations, and what things will cause it to differ from the real moon.
LikeLiked by 1 person