"Loud Sound Reduction" - what does it do, exactly? How is it different from "Adaptive" (AirPods Pro 2)

What EXACTLY does that setting do? How is it different from "Adaptive" Noise Control?

I learned from online docts that "Adaptive" does this: If sound is quieter than 85 dB, it passes it through (like "Transparency"). If sound is louder than 85 dB, it reduces it to 85 dB then passes it through. This is BRILLIANT for music concerts and dancing where the music is always too loud. I just discovered this by accident and I'm loving it. Way, way better than any of the earplugs like Loops, Eargasm, EarPeace (all of which I own)!

But what does "Loud Sound Reduction" do? How is it different from "Adaptive"? No online documentation anywhere. I even spent an hour on the phone with Apple, and no one could find an answer. Is it the same, except it's a preference in Settings instead of in the clickable noise control modes? Is there a different threshold before it kicks in? Is it more transient? Does it respond only to sirens and construction site noise (per Apple's vague description), but not to music? What's the real story?

Are there any engineers out there who know the actual answer? I hope so.