According to the Textual Commentary entry for Colossians 1:7-
"Although on the basis of superior Greek evidence (P46 and early Alexandrian and Western authorities) 'hemwn' might seem to be preferable, a majority of the Committee, impressed by the widespread currency of 'humwn' in versional and patristic witnesses, considered it probable that copyists introduced the first person pronoun under the influence of the preceding 'hemwn' and the following 'hemin.' " (see, pp.552, 53) [sorry, no Greek font]
Reading between the lines, I think that Metzger was the minority opinion here, and he wants us to know it, but my questions are,
1. Ought a bare subjective guess based primarily on internal and versional evidence hedge out such strong external considerations, including original hand Aleph and D, and also B and P46, et alii, and with such confidence that it rates a B?
2. What new evidence arose that prompted the "C" rating in the UBS 3d (corrected) to be upgraded to "B" in the 4th ed?
Robert W. Mossotti, Esq.