At what point in his swing do you think 4 is being released?
I would say that 4 is not being used if he mimics "the old two-hand basket ball pass" (p.98 of Five Lessons, 1957)
There's no question that it is being released or the club would go right over the ball . . . the question is in what fashion is it being released . . .
Test drive it . . . look at somebody like Nicklaus or Hoch vs. Sergio or Hogan . . . for your hands to work that close to your body #4 has to work different.
For the club to get around and the handle to stay low the left arm has to work different . . . watch how much lower the club "exits" for Hogan vs. Jack . . . Jack's club and hands come up thru between his neck and ear . . . Hogan's are below his shoulder . . .
To get there you gotta move a lot of stuff different . . .