Is extensor action at address ok?

[tongzilla]

Except with Zero #3 Accumulator, the stretch (Non-Accelerating Thrust) of Extensor Action -- whether executed by Pressure Point #3 or #1 or both -- is not On Plane, i.e., toward the Impact Plane Line. Instead, it is Below Plane -- in the direction the Left Arm is pointing.

Exactly.

When I first learnt about this, I thought 'cool, but how's this going to be useful for my own swing'.

After a bit more incubation, I realised that that's one of the ways you can differentiate between an Active Right Arm Thrust and Extensor Action. You can feel the Right Arm Thrust going directly at the Ball, whereas the stretch of Extensor Action is clearly below Plane. Learn to feel the difference! It’s very useful especially if you’re Swinger because you don't want to be inadvertently activating that Fourth Barrel (Accumulator #1)!