The Book Switch Theory

[ReneZ]

Additionally, as Anton pointed out in that other thread, the sequence  number of 4 should logically precede the later book with Nr 7 which had an even earlier date of 1602 associated with it.

That is based on an assumption ("logically"), and if our observations do not fit with some assumption, one should revisit the assumption.

Unfortunately, this is an inherent problem in many, if not most Voynich theories, not just the book swap theory. Often they are based on numerous assumptions, which are rarely stated, and not even always properly realised. They take as much importance as evidence, which is of course invalid.

Fortunately, assumptions in this thread have been clearly numbered in a post by Stolfi, and it is easy to see which ones are based on no evidence at all.

Anyway, the year 1604 is already explained on the web page. Note also that the 4 in the number and the 4 in the year are in quite different hands. 

Even though Tepenec's testament (including documents of its execution) has been found, it does not include the much hoped for list of books. We don't know if this ever existed but it would have been nice.