Has anyone figured out how the scaling for Fleurety works when MLB? Is it 0% special atk at 100% hp and scales linearly to 50% at near death or does it start off at non-zero and/or some other scaling?

I assume the upcoming light raid eidolon uses the same scaling, and am trying to figure out whether it's worth using her as a main instead of Barong, which is what I currently use.