Sorry to dispute you, Michael, but you are mistaking two different churches.
I don't see any dispute at all.
Essentially they are two different churches. Some Catholic apologists conflate the two.
Italo-Albanians and Italo-Greeks are not the same, I think.
And if they are I am not aware of their ever being out of communion with Rome. Transfered jurisdiction to Constantinople for a period, but not out of communion with Rome..
The Catholic idea is that the Italo Greek church somehow survived the five hundred years and was reinvigorated by these Orthosdox migrants from Albania.
Padre Ambrogio has maintained in the past (perhaps I should let him speak to this, but whatever) that the Italo Greek church died, disappeared and is gone. That was the church which, due to political circumstances, was subject the the Pope of Rome at the time of the Bull of excommunication 1054AD. It was also the church that was beginning to be actively suppressed prior to that (the reason of which Patriarch Michael closed Latin parishes in Constantinople in response).
This situation continued for some time, as Latin bishops were appointed to the Greeek Sees, these dioceses were all eventually converted to the Roman Catholic dioceses of southern Italy.
The migration of Albanian Orthodox (who most definitely were out of communion with Rome in the Balkans, and still are) was an entirely different case...500 years later.
It is the Italo-Albanian (formerly Orthodox) church which is usually claimed to have never been "out of communion" with Rome, but in fact it is a latecomer.
Grottaferrata seems to be a unique case, being a monastic foundation. It originated as an extension of the Italo Greek community, but somehow during the process of the Greek church collapsing into the Latin it survived. Most of the 1000 Greek Catholic monasteries of southern Italy closed, this one remained open, substantiallly Latinized. It has no direct connection to the hierarchy of the Italo-Albanian church (which was erected later), and is not counted as an institution of that Sui Iuris church.
It seems possible that the claim that the Italo-Albanian Sui Iuris church has continually been in communion with Rome is a product of creative thinking on the part of some imaginative apologists.Michael