@Michelle
In the discussion of this kind it's important to clearly distinguish between the solar cycle and the lunar cycle, as well as between months and Zodiacal signs. Where the solar cycle is concerned, Astrology divides the year into twelve roughly equal (in contrast to the actually observed unequal time periods) Zodiacal parts. Since the number of signs is equal to the number of months, there is then the idea to associate Zodiac signs to particular months. Perhaps it's not a good idea since the alignment is not strict (meaning e.g. Aries spans from March to April), but anyway the person who left the extraneous month names evidently had, for some reason, supposed that the intention of the VMS author had been to designate months (and not Zodiac signs per se) with these diagrams, in spite of Zodiac signs being clearly depicted in the centre.
Given this overlay of months (by a later reader) onto signs (by the VMS author), it's easy to fall into the trap of confusing months with signs, while in fact "omitting Aries" is not the same thing at all as "omitting March".
With trying to correlate Cod. Sang. 678 with the VMS, we are falling into this trap. In Cod. Sang. 678, the table does not refer to the Zodiacal cycle at all. It refers to months explicitly. Where the text mentions Zodiacal signs, it relates to lunar mansions, as far as I understand. Which is altogether different thing not related to the ecliptic and the solar cycle. So when the author of that portion of Cod. Sang. 678 omits January and February, he explicitly omits months, not signs (those of Capricorn and Aquarius).
What was meant by the VMS author - were it signs (as depicted) or months (hidden behind the sign emblems) - remains an open question.
ADD: as to the example of referring to good or bad calendar periods (as opposed to the Zodiac signs) in respect of bloodletting, the same Cod. Sang. 678 provides such example, as I initially quoted that above (the three "appropriate" days in the year).
In the discussion of this kind it's important to clearly distinguish between the solar cycle and the lunar cycle, as well as between months and Zodiacal signs. Where the solar cycle is concerned, Astrology divides the year into twelve roughly equal (in contrast to the actually observed unequal time periods) Zodiacal parts. Since the number of signs is equal to the number of months, there is then the idea to associate Zodiac signs to particular months. Perhaps it's not a good idea since the alignment is not strict (meaning e.g. Aries spans from March to April), but anyway the person who left the extraneous month names evidently had, for some reason, supposed that the intention of the VMS author had been to designate months (and not Zodiac signs per se) with these diagrams, in spite of Zodiac signs being clearly depicted in the centre.
Given this overlay of months (by a later reader) onto signs (by the VMS author), it's easy to fall into the trap of confusing months with signs, while in fact "omitting Aries" is not the same thing at all as "omitting March".
With trying to correlate Cod. Sang. 678 with the VMS, we are falling into this trap. In Cod. Sang. 678, the table does not refer to the Zodiacal cycle at all. It refers to months explicitly. Where the text mentions Zodiacal signs, it relates to lunar mansions, as far as I understand. Which is altogether different thing not related to the ecliptic and the solar cycle. So when the author of that portion of Cod. Sang. 678 omits January and February, he explicitly omits months, not signs (those of Capricorn and Aquarius).
What was meant by the VMS author - were it signs (as depicted) or months (hidden behind the sign emblems) - remains an open question.
ADD: as to the example of referring to good or bad calendar periods (as opposed to the Zodiac signs) in respect of bloodletting, the same Cod. Sang. 678 provides such example, as I initially quoted that above (the three "appropriate" days in the year).