Is there any character like that?

[cvetkakocj@rogers.com]

Anyway, these kind of illustrate my point. There is a clear difference in context between EVA o and a. These contexts roughly correspond to one of the two forms. So even when many utterances are imperfect, we still end up assigning them to different characters.

In the VM, there is a clear difference between a and o, although some letterforms a and o are not that perfect, however since there are no diacritic markers to differentiate short and long vowels, the pronunciation might be different, because the short vowels are often pronounced as semivowels, or they are not written, which is often the case in the VM.
Phonetically, there is a lot of confusion as far as the pronunciation of a and o is concerned. In some Slavic languages, o and e are often pronounced as a. This form of sound change is called akanje. That does not mean that there are no sounds o or e in those dialect, but rather, that there is greater variety of spelling. Similar sound change is in some words causing the letter o to be pronounced as u. This is called ukanje.
One needs to know the language to adjust phonetic Voynich writing to a written medieval form.
By the way, the Latin letterforms u and w are not yet recognized as separate VM glyphs.