Am aware... still, the issue here is with the loss of energy when dispersion is used - makes it unusable with clamping.
IMHO, in archviz, product & jewelry viz this is one of those details that either make or break the deal.
Cycles FAKE dispersion:
Maxwell Render 100% dispersion:
Quite much inconsistencies in values among different engines so i'm gonna continue exploring, comparing, searching for optimal solution and post notes/thoughts here. I guess learning & correcting mistakes (fixing bugs) never ends. & Of course, am gonna use LuxCore with proper/better values, yet still do tests with others engines: Indigo, Ocean, Iray, VRay, Octane, RedShift, appleseed, Arnold, Corona, PRMan...
Tho strangest thing, except Cycles, no other engine i know off (even those that claim to simulate physically correct - ground truth) uses multi-scattered GGX model, which in most cases helps a lot in realistic shading. I remember how fast had been implemented in Cycles. But lots of other stuff is missing, so...
... the traveling continues.
Thanks again and keep the genius alive.