Yes, I'm not sure if Arabic Parts are parts of astrology or not. The question here is whether or not any Modernists, ie modern astrologers, used them as part of their modern astrology practices or not. I'm not sure if transits, as you say, are an exclusive part of their use.
Since the Uranian school of astrology (the Germans who invented it did not refer to the astrology they did as that, but as kosmobiologische) invented them, one might assume transits of Uranus might have played a part in their use, or maybe Aquarius.
I think that's partly right.