@Mauerwegler - Totally agree - in most cases. In this case, my zones were not correct originally because of the way my older watch worked w/ the app, but I didn’t use Suunto’s data except to load into TrainingPeaks (where they were correct) so it didn’t matter.
Since I am now using Suunto’s data more I was just hoping there was a way to update like in TrainingPeaks which solves both problems - you can re-calculate old workouts with the ‘new’ zones, but by default ‘new’ zones only apply to future workouts.
But yeah, I’m not concerned going forward - just had to manually edit the hrTSS on my first few workouts, but all good now.