Lets assume Mandrin and Zick are correct, and they is no "heavy hit"...
...or "Accelerating Hit."
If you understand the physics of impact in the basic form, you can answer this question:
How do you have two shots, with the same club, both sweetspot contact, both with the same clubhead speed at impact, but with a different smash factor?
It's pretty easy, but the first correct answer is King for a day!
the long drivers don't they use low lofted heads, like 5 or 6 °s and then use a positve launch angle some thing like 12 or 14 to give them more ball speed.