Tropical Astrology and the seasons?

I know a few Australian astrologers and they use the signs the same way astrologers do in the northern hemisphere, and they report it works fine. I have to admit, however that this is a bit uncomfortable. Astrology was developed in the temperate zones of the northern hemisphere and it is based on the seasons of the year. IF the basis of the subject is reversed, it seems natural that the subject should be reversed in some way. Yet one of the worlds' better known astrologers, Bernadette Brady, began her studies in Australia and has done very well with it including making something of a splash years ago by out predicting the experts in a season's worth of Australian rules football using William Lilly's methods for determining the best time to besiege a castle. Brady didn't even know the rules of football when she did this. Do with this information as you see fit.