I may be simple minded but I don't understand how Mustad is renumbering their "Upgraded" hooks.
They set up a new numbering system in which a last digit is the shank length in the regular "X" designation but then they add an old hook number so we can do a translation.
The problem is that the "X" designation that is built into the old hook number is that of a different shank length. I can't see how one hook can be described as having TWO different lengths