Then the date would have to be re-calculated because knowing this new date could cause the date to change in a different way, requiring another recalculation, e

Then the date would have to be re-calculated because knowing this new date could cause the date to change in a different way, requiring another recalculation, etc. I guess it really depends in practice, might only be a few loops before it gets stuck on one date, could see it being an infinite loop though