Yep, that's a mistake, unless it's just a difference in the way the series' continuity evolved in the different universes. The Amazones Quartetto (to use the version of the name which has the best "that's-what-she-was-trying-for" argument among those I've seen) were from SuperS, and the Dead Moon Circus; the Black Moon Family's four women were "ayakashi no yon shimai", literally "weird/strange/eerie four sisters", commonly rendered "the four Ayakashi Sisters". Whether the error is in the name for the four women, or the name for the evil group, is another question.
Hmm... odd; I'm not finding "ayakashi" in my dictionary, even though I'm quite certain I've seen it there before...
Hmm... odd; I'm not finding "ayakashi" in my dictionary, even though I'm quite certain I've seen it there before...