Welcome Pridders,When you depress the accellerator pedal, up to the point you mentioned where you feel resistance, you are using straightforward in-gear accelleration. Beyond that point (for the last 1/2 inch) it recognises that you still want more and this is the kickdown section of the pedal. If you are in a higher gear and a lower gear would give you more accelleration then it will kickdown into a lower gear. Sometimes you may already be in the lowest available gear and in this case it will simply stay in the same gear until the limit is reached and then gear up.
what's the benefit of using kickdown over the paddles? It seems a bit n00by-ish to me