Part of Zodiac was added later?

[ReneZ]

There are important matching details between the illustrations of many different sections. Some examples:

- large plant drawings (herbal) are repeated in the small plant drawings (pharmaceutical)
- containers in the pharmaceutical part are also found with similar design in the rosettes
- some circles in the rosettes are similar to individual cosmological drawings
- the top left circle in the rosettes has similar details as one herbal drawing
- the nymphs in the zodiac section are similar to those in the biological section
- the stars in the zodiac are similar to those in the astronomical and the recipes sections

Certainly many more details can be found.

While this does not necessarily point to a single person (I have no qualification to judge this), it is all a very common design.