I said don't get wrapped around the axle about all the charts and graphs. Not because the science doesn't matter, but because there's more to it than that. If studied those charts (and more). If all you look at is a couple of charts, you'll miss the big picture.
But, back to the main point. There is a minimum operating temp for engine
oil. I have searched for what that is, exactly, but the answer seems to be variable. Some engineers say it's 180*. And some say it's 220*. So I'm not sure. But it certainly seems to be no less than 180*.