In Hollywood week, she blew the doors off of "Living For City" and even though she screamed a little in that song it had NOTHING to do with why the judges picked her. When she growls and sings things with a strong voice, that's when she kicks ass! Her low register sux!!
If you go back and listen to "Living For City" and "Think" other than the screams, she delivers some vocal and stage presence moments in those songs which are brilliant.
I just took (the coherent parts of) that as basically being "yeah, I played it 'safe' this week, because making the tour is so important, so I just went with what worked for me before."
Part of her appeal and charm is unpredictability, so she really does need to start mixing it up a bit and avoid getting "formula".