VMs: Is an "o" always an "o"?

I am curious at to what the general consensus is concerning the Voynich "alphabet"? Can we say that each "character" (symbol, glyph, etc.) always represents the same "character" wherever it appears in the manuscript. Statistically speaking, isn't it most likely that this is the case and that the "characters" are not being generated through some exotic encryption key. Just the placement of the letters throughout the manuscript, the easy flowing, almost predictable manner in which they appear in each of the "words" would probably rule out any key controlled text I should think, unless my lack of understanding of cryptology is so naive that I miss numerous alternative possibilities for encoding the text. If we can agree that an "o" is an "o" no matter where it occurs or what it stands for, then perhaps we can focus our efforts on finding a key association between the text and the drawings. It is just a thought and probably impossible to say with any degree of certainty, but then again maybe the cryptologists and linguists can say with a high degree of probability that "yes" an "o" is most likely an "o" in every case throughout the text. As for the "4o" combination, I am reminded of "qu" in English.