Totally agree. I incorrectly implied that the flapperons are fixed. They are not. This is also true of the programming on a model. The flapperon when deployed will still move slightly with roll input but since they are near their max deflection, they move much less in comparison to the Tailerons. There are a few rough landings of the SU's where as it bounces on one wheel and then the other you can see the flapperons move either by the stick or FCS. Other times you can see these one wheel landings and they add a snap roll correction with the taileron moving quite a bit, but the flapperon movement is not apparant.
I took this to be and FCS setting depending on the pilots choosing. I'll ask my relatives again what the setting are.

For the F-35 its hard to tell which is favoured since there is so little clear footage. But they are using all the surfaces in many of the test rolls, air braking and landing configs. Just not sure which is the dominent but from some footage it appears to be similar little movement in the ailerons and more roll correction in the tailerons.

I've found them not to be the same for say a Cobra. I had a hard time getting a stab/elevator to cobra well. Tailerons or stabilators, there was no issue.