I used to use the HHT constantly, but now I never do. The reason? I'm using different hones now.
In my experience, the type of hone used has a lot to do with how a razor does on the HHT. With my hair, it works perfectly for the Norton and some of my barber hones.
On the Belgian hones I'm using now, it's almost worthless. Even a great shaving edge will just split and peel the hair rather than cutting it cleanly. This was really confusing for me at first, but I checked with other guys who use coticules and they confirmed this.
Lynn uses a coticule after the Norton, I believe, so that could explain why your Lynn-honed TI didn't do well on the HHT. It probably would have passed with flying colors if you'd tested his edge before he used the coticule on it.
I agree that passing the HHT is just a starting point. When I was using it a lot, I usually got the best results off of the 4K side of the Norton. To me, what a good HHT result means is that you've got a good bevel--in other words, the two bevels meet properly to form an edge, and the edge doesn't have a wire. After that, it doesn't always correlate well to a good shave.
The HHT seems to be one of those YMMV things. It's unfortunate, because a good "works every time" test would shorten the learning curve for honing. But like Lynn says, that test is shaving.
Josh