Well, I think the Belgian yeast covers up anything you'll be able to reliably tell, although 66 tastes could tell, which I thought was staggering.
A future exbeeriment would be to test a 60/60 145/162F step mash on a helles. And I'm surprised there was no mention of the mouth feel of the beer. The hochmash was short, but should've provided at least a bit more body. And someone mentioned earlier about no wheat being used, which is typically the main malt when used in conjunction with a ferulic acid rest.
I definitely think there is some merit to step mashing. Do you think the Germans would spend so much time making their excellent beer if it was all for naught? I know I can perceive a difference. Even if it's subtle, it takes, what would be a good beer, to a great beer.
Dave, I don't think beta and alpha amylase enzymes are working at full power in a 150F rest. Just like yeast, there are temperature ranges where they work best and provide the most benefits to the wort profile.