He's right on Spektrums and JR's "+" is LESS sensitive around center.

Minus settings make the plane more twitchy and harder to control.

Remember that you DO NOT want to over do it on Expo.

Expo is a way of re-obtaining the linearity of stick to control surface movement.

If you go too high on expo ( say well over +50% ) you are pushing most of the movement to the extremes of stick travel.

That means the plane will not appear to be too responsive around center stick, but as you move the stick to the side to compensate, control surface travel ramps up quickly, which results in you overcontrolling the plane.