Originally Posted by Werty Yui

The confusion here is the fact that you're using a 4PX as your main radio. Historically, and I'm not sure if things have changed since I last owned a 7PX, when you want to apply negative (less) "Expo" to a channel on a Futaba radio you hit the (-) key and the graph move in a concave pattern. On most other radios, if you want negative expo, you'd actually have to hit the (+) key to "add slowness" and the graph would take a concave shape. The fact that the graph moved in a convex pattern shows that you're hitting the (-) key on the Noble which is INCREASING expo unlike a Futaba where is takes away expo.

You're basically trying to set expo on the Noble the way you'd set it on your Futaba and the technique is not interchangeable.