Stepper motors and ball screws have been used in CNC since maybe back in the 1950s (maybe earlier, that’s the oldest machine I’ve ever seen). They are highly repeatable. If they weren’t, they’d be no good for CNC. My bench-top Taig CNC will move back and forth along all 3 axes all day long and always come back to the same spot (plus or minus maybe a half thousandth).
There are two factors that reduce repeatability, lost steps or high backlash. Lost steps happen if the stepper is overloaded, either asked to move too fast or the motion path is obstructed. Backlash can make the positioning system sloppy (it’ll move a little if you push/pull on it), but it also introduces an offset in the absolute position reference as a function of the direction of the current move relative to the previous move. If the next step is in the same direction as the last move, the backlash is “taken out” already and the motion stage moves exactly as far as it’s supposed to. If the move is the opposite direction of the previous move, the distance the stepper moves has to exceed the backlash before the motion stage will move.
The F3 build stage moves up a fair amount during the print to make room for the wiper to sweep. That move is much, much greater than any possible backlash that might be present (because that’s going to be very small or the printer wouldn’t work correctly). So it doesn’t matter if it moves even further, even all the way to the top of the stage. The increased distance contributes nothing to positioning error unless the stepper loses steps along the way. In which case, the machine is busted somehow, since if it’s working as designed that should never happen.