I agree; Unfortunately since I calibrated, it does not change the fact that there is some sort of a curve FSX has seemingly dedicated exclusively to the aileron axis that makes the last 20% or so of your joystick's travel amount to around 60% of the airplane's total aileron travel distance. Unless I've misunderstood what calibration is for (setting up the maximum and minimum range for your joystick along with deadzones) it could not affect this issue.
edit: Your post did stimulate a part of my imagination that inspired me to try changing the joystick's curve to a negative level though, which solved this issue. -15 curve in the FSUI calibration window did in fact, make the travel almost linear.
It's ever so slightly short of linear however, which makes me motivated to ask Mr. Dowson this:
Would you please consider adding an extra +-5 into the slope options in your next version of FSUI? That would undoubtedly solve this issue for me, and others as well as adding another slight amount of customization to the already large amounts of customization already included with FSUI. ALSO, it will allow me to finally get back to happily flying my imaginary airplanes :D
Thanks a bunch to everyone who participated in this thread and especially to Mr. Dowson and user Andydigital, for helping me come even closer to solving this issue!