My FSUIPC version is 4.971.
When I assign either ELEVATOR SET or RUDDER SET function to any particular keyboard key with a parameter of 0, it centers elevator or rudder for only 01 time. Afterwards if I again move elevators or rudder and again tries to center them by pressing the assigned key, it does not works. Then if I again re-assign that same key with a different parameter value then it will move the control surface to that position only once and then again it stops working. Again on re-assigning with parameter 0, it will move the control surface to center but only once.
Bottom line: it works for only 1 time and then stops.
Kindly find my log file attached herewith.
Regards.
FSUIPC4.log