Thermostats - high flow vs standard flow - now I am confused

I think my Hi-flow, is called a hi-flo for two reasons; #1, it opens WITH the flow instead of against it, and #2, it has a huge opening when it is fully open.
My Milodon was new in about 2001 or 2002. It was deadly consistent, including a fast warm-up, and it is still in the car today.