To clarify. I believe that the quadruplicities [Cardinal, Fixed, and Mutable], as like the Sabian Symbols, are tied to the Tropical Zodiac, that they are bound to the Seasons and have nothing to do with the Sidereal. The Spring equinox is a Cardinal event, that moment when the length the waxing of the hours of Sunlight then start to wane, the culmination of the Mutable, etc.
Regardless of what Sign and degree of that Sign is at the moment of the Spring Equinox, the Sabian symbol associated with the first degree of Aries is always in effect. The same goes for the quadruplicities.
[Gee, if there are only three of them then why are they called the quadruplicities? Wait for it, someone will eventually ask that question. ]
12 zodiacal sign divided by 4 = 3