Whatever it was (or wasn't) it appears to be gone and un-replicatable so who the heck knows.
That it moves in 1 and 2% increments up and down seems to be something about the math that IL-2 uses to read controls. One needs devices with massive amounts of resolution (if one changes sensitivity one can see that it moves in 1% consistently, on devices with already high resolution, but not otherwise). I suppose that the different numbers you see on the way back could be either the strange IL-2 math or that the reversal bug fix is slightly too much or too little, so you might be able to get it completely consistant with some of that tweaking.
When tuning the amounts originally myself when seeing if it could be done or not, I used the AutoHotKey (the programming language I made this stuff in) debug features where I could see the exact indicated positions of the axes, and then I would check how much one 'normal' step was, compared to how much the fix was 'off', then adjusting over and over until they matched almost exactly. But each throttle was a bit different, and other throttles can be too. Unfortunately for you there's no way to see the numbers straight, all you have to go on is the in game %, which could be unreliable.
Either way, changing that value by some fraction cannot be responsible. Even if set to crazy amounts it would not influence the other throttle in any way.