Having acquired a U2 with Trail Loop to replace my S3 with Sport Loop (still kickin', albeit slowly), I've noticed that Apple has flip-flopped in how they orient the bands between the two situations.
Instead of positioning the pass-through buckle on the bottom lug, as on the Sport Loops, they've reversed it and put it on the top lug with the Trail Loop. It does seem a bit off to pull "up" and not "down" to tighten the strap after being accustomed to the latter for so many years with the Sport Loop.
In the pragmatic sense, it can be installed and works either way, with not only these two types, but most of the others, and certainly the symmetrical elastic bands, but it still piqued my curiosity.
With the Trail Loop, I suspect the protruding pull tab may have played a role in prompting the reversal, but that's just a guess.
I also suspect that most users don't notice or care how they install their bands.
Instead of positioning the pass-through buckle on the bottom lug, as on the Sport Loops, they've reversed it and put it on the top lug with the Trail Loop. It does seem a bit off to pull "up" and not "down" to tighten the strap after being accustomed to the latter for so many years with the Sport Loop.
In the pragmatic sense, it can be installed and works either way, with not only these two types, but most of the others, and certainly the symmetrical elastic bands, but it still piqued my curiosity.
With the Trail Loop, I suspect the protruding pull tab may have played a role in prompting the reversal, but that's just a guess.
I also suspect that most users don't notice or care how they install their bands.