Luke is advocating for one test per ability per scene (as per Burning Wheel core rules) and that “Skills Being Learned” are purely stat tests. Luke’s advocacy is that if you’re learning Persuasion and Oratory that you can only earn a test towards learning one of them per scene and not both (and that a Difficult or Challenging test for Will would block either of those for that scene).
For the record, I play the same cheaty way that Thor does.
Luke’s response to the first part of the question seems to indicate a D/C test would block the beginners luck test, just that you only get one beginners luck test per scene.
Oh, huh. That’s actually a bit odd. I’d say either one beginners luck test per skill plus a Difficult or Challenging OR one Stat test period (with the bigger one (Difficult/Challenging) blocking or nullifying any previously earned beginners luck checks).