Codex Vaticanus Graece 1209, B/03

The word-order umlaut

On page 1446 a strange umlaut appears: An umlaut with a little vertical wave added. This is the only time in the codex that this special kind of umlaut appears. The text is Rom 1:29, a list of human wickednesses.

The word-order umlaut, p. 1446     peplh
    rwmenouV pash adiki
    a, ponhria, pleonexia,
    kakia, mestouV, fqo
    nou, fonou, eridoV,
    dolou, kakohqeiaV,

There are several known variants in this verse.
At the line of the umlaut we have the following word-order variants:
ponhria, pleonexia, kakia     B, 1739 pc
kakia, ponhria, pleonexia     C, Dc, pc
ponhria, kakia, pleonexia     01, A
Other variants are:
porneia, ponhria, pleonexia, kakia     Byz
kakia, porneia, pleonexia     D*, G

It is clear from this evidence that the umlaut indicates a word-order variant. The following things are irritating to me:
  1. I know this symbol, a curved line, well. It is still in use to indicate word-order. How old is this sign? Are there examples from the 4th to the 10th CE?
  2. The umlaut looks very "new". There is not the slightest bit of old ink visible. Old ink is clearly visible at all letters on the right. The ink of the umlaut is dark and it is written with a very fine pen.
Is it possible that umlauts have been added later? I have proposed this already in the introduction to the umlauts. There are umlauts that are unenhanced and therefore probably very old. On the other hand there are umlauts which look rather "new", like this presented word-order umlaut. Is it possible that we have a mixture of umlauts from differents times? Would be rather annoying!
Comments welcome!