Quote Originally Posted by Sapphidia View Post
If anyone can actually confirm the mechanics of interrupting and health threshold though, I'd be grateful - this is from word of mouth and casual tests so might be incorrect.
I'm pretty sure there's a damage threshold for an interrupt, but I'm not sure what the value is. I've only had one clemency cast interrupted as PLD, but I also got blasted with a crit for the interrupt, so I don't know if it was the crit or the damage that did it.

Anyway, OP, ShO/SwO are spells, so they interrupt combos. Defiance/Deliverance are abilities (which don't interrupt combos), and the "tank bonus" for Defiance doesn't come into play unless someone hits you with a Lustrate/Tetra immediately after you pop it; ShO is an instant -20% damage taken, so yes, it has a penalty associated with it.