If I was getting the result I wanted, I don't think I would change it the night before the shoot just because someone said something.... even if that someone was an expert. I might take a backup camera with the new setting and might shoot concurrently, however.
If it is an indoor portrait, you aren't likely to encounter extreme brightness range anyway.
Based on my personal experience, I got a good result shooting Delta 3200 at ISO 1600 and develop it as if EI 2400 but that's with my camera, my developer, and my thermometer....
Seriously, I won't fool would what works this late in game.
Mark Barendt, Ignacio, CO
"We do not see things the way they are. We see things the way we are." Ana´s Nin