They do this in order to make you notice that there is problem. If they made it so that the ride is smooth, you may not notice that there is a problem with the suspension.
I received call from the Lexus sevice rep today telling me that I had a bad right rear height sensor and a bad height control motor. The repair estimate is $2700.00!! I am taking the car from them and will have my local mechanic replace the height sensor and see what happens. I know a Lexus tech who told me he has never seen a height control motor need replacing. To be continued.