...Herbo: that's EXACTLY how a camera works! That is why it's unsettling to have a different behaviour for the rendering!
Attached abstract from "View Camera Technique" by Leslie Stroebel.
I understand your request, we will discuss that. But your interpretation of the equations is wrong. Just because there are two planes of equal CoC (circle of confusion) in front and behind the focal plane does not mean that they are independent from each other. In fact, they are not. The camera parameters boil down to one degree of freedom that controls the CoC w.r.t the focal plane.
But anyway, I understand the request. Sometimes it might be useful to bend the laws of physics for artistic freedom. We will discuss that.