Then do NOT allow the Calendar to stand in the way of unification!
Ignatius IV Hazim - Enlightener of the World
Because the Old Calendar is wrong, broken, in need of being fixed, etc...
If accuracy is so important to your church, then why did you choose the inaccurate and errant Gregorian calendar as the model for your new calendar and not the other ones which used 20th century technology and were also presented to your leaders in the 1920's?? Obviously accuracy was not important, but something else was.
The Julian Calendar, which the Church Calendar is based on, was already off by a several days when the Holy Fathers set the date of Pascha - and they knew it. They knew it then and they certainly knew it when they repeatedly rejected the popes calendar in the 1500's. The pope, concerned with worldly things, and along with his "scholars", schoolastics, inventors, astronomers, and scientists, also told the Holy Fathers in Constantinople the same as you, "...the Old Calendar is wrong, broken, in need of being fixed."
There seems to be no shortage of people today calling the Holy Fathers "wrong" and in "error". Do these people really expect that I would choose to stand with them and the pope in their insolence and error, than with the Holy Fathers? I suppose it is hard to see the spiritual light when your church has walked away from the Grace of God - they are as much in need of spiritual guidance as any other "christian" group I suppose; and they only seem to maintain a resemblance to Orthodoxy in the same way as hair grows on a corpse - eventually even that too will stop.