I'm not buying this "ass reduction" narrative unless someone has a screenshot of her outright stating it. It's already surgically enhanced and is quite literally her breadwinner, so the idea that she'd reduce it, and by an amount most of us probably didn't even notice, doesn't make sense unless it was some medical issue like the last job having been botched.
I think it's probably far more likely that she has regular upkeep work done on her ass and stomach, and this time round it's made her ass look slightly firmer and less jiggly. But even saying that, I didn't notice a change at all until this thread pointed it out.