Sorry. I answered my own question...
My thing is it sounded like she REALLY hit it instead of her just faking it like some singers I've heard of, because I've mostly heard her get up to a high F, thus THINKING that she was a mezzo-soprano. She nailed a high G when she closed out the "ABC Daytime" concert at New Amsterdam. Before Miracle Brothers I hadn't heard her get that high, but I figured out that she was a part of the off-stage chorus vocals for BatBoy, and I bet she hit some of the really high notes.
"How could she just suddenly, completely disappear into thin water?" - The Little Mermaid