Though much closer I'm still thinking not quite there.
The option does not change the actual slope or topography of the green, it mearly changes the speed at which the dots move. The issue was that the dots in Flash move 2 times the speed of PCEA (for the same slope) so players changing over to PCEA were misreading their slopes as it looked much less than it actually was as the dots moved at half speed.
if you hit the same putt in both modes (Standard/Classic) from the same spot on the same green they will obviously go to almost the exact same spot because it’s the exact same shot.
if you go to the Hard green have a look at a spot with a more exaggerated slope. When you switch between the two options the dot should be moving across 1 grid square in half the time between the two options