Why not positional variation?

[Koen G]

I just did a quick check on voynichese.com where I got 2 instances. Might just be the different file used.

First one matches, that's f14v. 
On f57v, Voynichese gives okoldm vs. okaldg in your file.
On f68v3, opcholdg matches.
Finally on You are not allowed to view links. Register or Login to view. we have Sheoldg vs. Sheol.dg

So you get a 100% increase depending on the transliteration file used.