Thanks K.
that wasn’t the case, but it did made me think that maybe the interpolation time frame, (the time the ease in/out is taking) is just covering all the frames that I want it to stop…
reducing it to 5f like so did the trick:
slider = thisComp.layer(“Null 1”).effect(“Slider Control”)(“Slider”)
period = 25
tPeriod = framesToTime(5);// <—————here
seg = Math.floor(time/tPeriod);
t = time%tPeriod;
v1 = slider.valueAtTime(seg*tPeriod);
v2 = slider.valueAtTime((seg+1)*tPeriod);
ease(t,0,tPeriod,v1,v2)
and gave me this beautiful result:

if I want to have the interpolation go above 25f, I need to get the slider’s x value up:
x = 100; //<—– for example.
f = thisComp.frameDuration * x;
posterizeTime(1 / f);
Math.round(random(300,600))
so… thank to Dan again, and to K off-course.
cheers,
Ido.