I think you're right. With road tubeless, there's a school of thought that lower pressures, to a degree, provide less rolling resistance than somewhat over-inflated tires bouncing down the road, and that's one of the selling points. However, there's a point, obviously, where too little pressure causes the tire to not roll as easily, either. With the Hutchinson 28's we're talking about, I'm getting really excellent ride quality on bumpy pavement and the tires still "feel" fast, whatever that means. Again, I've been running them in the 80's. If I were to ride some particularly crummy roads with them, I'd probably go a little lower with the pressure. Rider weight makes a difference, too. I weigh 160 FWIW.