I've found the author of Voynich manuscript. He was Giovanni Aurispa.

[ReneZ]

Doesn't that make it 2 letters? That would make it 5 characters.

Possibly, but it still means that half the characters of the word (balaustiis) has been added 'out of the blue'.

Then, to make it worse, the first k may not be a letter at all, but rather a start marker.

Also unusual is that the first word, the name of the flower, is in dative or ablative plural....