One of the great questions about the Chronicle of Eusebius is whether the format of the tables as given in the Latin translation by Jerome (numbers of years at the margins, text down the middle of the page) is Eusebian, or whether the format in the Armenian translation (numbers in the middle, text in the margins) is authentic. Mosshammer suggests the former, which is also reasonable on other grounds.
Jacob of Edessa made a continuation in Syriac in the 7th century. The format of this in the CSCO edition is the same as the Armenian version; numerals in the middle.
This suggests to me that a Greek text existed which had been rearranged but not continued, and which served as the basis for the two oriental versions.