Proper right shoulder movement is critical to delivering the power package correctly in my opinion.
If the right shoulder works under to much you are going to dump #3 pp early as I painfully had to learn.
Also I had been given advice not to over-accelerate the club head, thats the path to PP#3. Worst advice to for me, I would leave the club head behind and then my pivot would wonder off finishing the swing.
Acceleration, with proper pivot and plane lines, is the key to PP#3 in my opinion.