So, if my memory is serving me correctly, it would seem that the Byzantines are the anomaly when it comes to the Sign of the Cross.
Please see the Catholic Encyclopedia 1914:
" At this period the manner of making it in the West seems to have been identical with that followed at present in the East, i.e. only three fingers were used, and the hand traveled from the right shoulder to the left. The point, it must be confessed, is not entirely clear and Thalhofer (Liturgik, I, 633) inclines to the opinion that in the passages of Belethus (xxxix), Sicardus (III, iv),
Innocent III (De myst. Alt., II, xlvi), and Durandus (V, ii, 13), which are usually appealed to in
proof of this, these authors have in
mind the small cross made upon the forehead or external objects, in which the hand moves naturally from
right to left, and not the big cross made from shoulder to shoulder. Still, a rubric in a manuscript copy of the York
Missal clearly requires the
priest when signing himself with the
paten to touch the left shoulder after the right. Moreover it is at least clear from many pictures and sculptures that in the twelfth and thirteenth centuries the Greek practice of extending only three fingers was adhered to by many Latin Christians … However there can be little
doubt that long before the close of the
Middle Ages the large sign of the cross was more commonly made in the West with the open hand and that the bar of the cross was traced from left to right."