Spanish has been on 105.3, 105.7 and 105.3, 96.7, basically everywhere except the two class C’s (96.1 and 94.9). Every few years iHeart flips the format, moves the frequency, rebrands, etc but they normally have a station in the format. Before 105.7, Z was on 105.3 - which is a horrible signal for a Spanish language format. 105.3 is perfect for an urban format - as I’ve said many times before, its signal is almost identical to 104.1 WALR, and we see how well they do.
My guess is iHeart wants to keep Spanish in Atlanta (on a signal other than the dog 96.7), and knows even though it doesn’t do well on 105.7, 105.3 is even worse for the format. iHeart has been through so many Spanish incarnations in Atlanta - Viva (on both 105.3 and 105,7 at different times), El Patron (on 105.3 and later/now, 96.7), Z on 105.3, then 105.7. It seems like an endless cycle. I remember for a while in the 2000s, Viva and El Patron both did quite respectably.