From what I've read, high levels of ammonia can kill off nitrobacter, the bacteria that converts the nitrites to nitrates.
That said, if I were you, I would probably do 1-2 30% WCs/day. I've had a similar issue in the past but was fortunate that the ammonia didn't kill off the nitrobacter and it took two weeks to correct itself. Not thinking, I added a little bit of SL-Aqua Nature Soil about a week after my tank finished cycling for aesthetic purposes. I dosed Prime at, about, 1.5-2x the dosage every water change to deal with the ammonia. After two weeks, the tank restablished itself and I didn't lose a single shrimp. I will never make that mistake again.
Good luck.