Another way to look at "Bump steer" is that it is steering caused by bumps, ie, suspension travel.
In off road, bump steer settles the car in and helps with stability, believe it or not. A car with zero bump steer can sometimes feel wandery, but with some bump in you get more consistant braking, bump out seems to favor on power steering, since out on compression equals in on extension(during droop).
Of course we are talking subtle changes, like .5 degrees, etc. for example.
...Jim
W.E.D.