To my knowledge the 1 is methyl-dht-oxime
It doesnt actually lower estrogen per say, it just doesnt convert to estrogen. Therefore if you have an aromatizing compound, DHT-oxime wont convert to estrogen but it also wont prevent the other compound from converting to estrogen.
When alone, the whole idea of it being anti-estrogen I suppose comes from the fact that because it doesnt convert, the body is also no really producting it's own test(aka being shut down). No new test=no estrogen.
Hope that helps. If im wrong feel free to correct me.