The Heptameron appears to have an astrological framework which is in opposition to other contemporary Solomonic pieces like the Hygromantia and Key of Solomon. For example by extension of the reference of the winds we can trace its correspondences to the source-work of Liber Juratus which places the zodiac by directions attributed to the four seasons opposed to the more common northern and southern hemispheres. This places the spring zodiac to the east, summer zodiac to the south, autumn zodiac to the west and winter zodiac to the north.
It is possible that the winds stirred by the planets as mentioned in the Heptameron and Juratus are attributed to the direction of the zodiac where the planet is in its fall or detriment. The Sun for example would stir the Western wind under Libra or the Northern wind under Aquarius, etc…
By extension of the Munich Manuscript we see emphasis on the ascendant requiring planetary talismans to be created on the day and hour of the planet with the ruling sign on the ascendant. Similarly we see the same for making the angelic seals in the Elucidarium, the predecessor to the Heptmaeron.
The emphasis of astrological association to the ascendant and planets to the perspective of the seasons makes the Heptameron distinctly different than other Solomonic texts. There is less observance to the physical zodiac or actual placement of the planets in the heavens as the target day is based on the planet and the target hour is either the ascendant or the hour ruled by the planet (or both).
It does seem historically accurate to say the sign on the ascendant is simply the background on which the planets travel and that those signs give little effect to the power of the planet. The Elucidarium highlights this for making the seals for the angels. It tells us to craft them on the hour when under the sign (implying the sign is on the ascendant). It continues by saying if this cannot be easily done, just use the hour. This gives us the impression that there is some importance to the zodiac ascendant but not much. The Munich Manuscript also details using the ascendant sign when crafting angelic seals but there is no instructions to include the sign when making planetary ones.
Finally it is the opinion of several occult scholars (Mihai Vargejaru, Stephen Skinner, Joseph H. Peterson, etc…) that the emphasis of the planets as they relate to each other and the moon by aspects and similar astrological intricacies is largely unimportant in the Solomonic tradition. The emphasis of astrological considerations is applicable to image magic and astral magic such as the works of the Picatrix but does not apply to the Soloomonic tradition at large including works of the Heptameron, Hygromantia, Liber Juratus, Sepher Razialis / Solomonis, Clavicula and more.