ORIGINAL: rob10000
from a non-linear source (pushrod attached to servo wheel/arm)
Maybe or maybe not.
If the distance from the pivot to the pushrod hole is the same for the servo arm and the control horn, the two non-linear effects cancel each other out and the control surface tracks the servo rotation exactly. This is because your control linkage forms a parallelogram. The control horn will remain parallel with the servo arm.
If, however, the distance for the servo arm is greater than the control horn or vice versa, you will get an expo or reverse expo effect. This is because your control linkage now forms a trapezium.