Ahh, now I think to know why people say stack parry and dodge after reaching 102.4%.
If you think about EJ when you said "most theorycrafter", then it's missinterpretation. EJ doesn't suggest stacking parry and dodge after hitting full ctc. They are saying reforge back to avoidance, which is different than stacking. Stacking involves gems and trinkets (if available) too.
Why is this little difference important? Because you can't reforge to stam.