While the grill hole is parallax-occlusion mapped, the beveled edge is only parallax mapped. That is, if you look at it from a very steep angle you still get to see the parts that should be occluded. But it´s parallax mapped anyway so it deforms in a way akin to what the real shape should.
In the image above you can compare a real mesh to the procedural texture and see, that up to that angle at least, it is still very similar.
But as the angle gets steeper, although the illusion is still convincing, specially from far away (you don’t want to be looking at grills from this close anyway, right?), you start to see some discrepancies with the way I chose to map the distortions.
