Oils of differing viscosities having the same "flow properties" (viscosity?) at a given temperature makes no sense to me at all. Viscosity values are a measure of a liquids flow properties. If they were the same they would have the same value. I don't see where a 30 weight liquid could flow as quickly at any temp as a 10 weight. If it does it isn't a 30 weight oil, it's a 10 weight oil.
Conversly it's reasonable to see where a less viscous (thinner) oil could be made to have the lubricating properties (not viscosity) of a thicker oil at higher temps. I've drained a lot of hot 10W30 over the years that was WAY thinner hot than when it went in at room temperature.
I can't do it today because my car club is finishing up a big three day show but I will test the flow of 10w30 vs the flow of 30 weight at the same temperature. I'll make my own Zahn cup and prove to myself at least whether I'm full of BS or not.
