Along the lines of what Marco was thinking, the word month could be implied everywhere. "Astronomers reckon that the Sun enters the Signs at the end of the month, but Taurus at the beginning [of its month]. Indeed each sign is given to the month that deserves it by [containing] the end [of the month]."
This would result in the common practice correspondence of signs and months, not in the Voynich case.
This would result in the common practice correspondence of signs and months, not in the Voynich case.