Sounds to me that both of you should check your stick scaling in the Joystick set-up. To do this open your clipboard and select Options>Controls>Map controlers. Now check the ADVANCED box - upper left screen. Next check the ENABLE SCALING box.
Now. use your mouse to hilight the "Y axis (elevator) in the window on the right. Go back to the left side and select DEFAULTS. You should now see a gradual rise of scale sliders in the 0 - 90 columns. This is good. Click on OK back on the right side and repeat this process for the X axis (ailerons) and Z Rotation axis (rudder) Just be sure to check OK on the right side after enabling each default axis.
Finally, recalibrate all axes and you should be good to go with minimum bouncing around. Keep in mind that you can tweak those 0 - 90 band sliders for finer tuning. Please refer to the Aces High Help files, or Netaces.org for further info on this matter.
Holler back if you need further assistance. Good luck!