I think this is true. A very good drill for precise low/high positioning is the Wagonwheel Drill which was promoted by Ted Brown. With a short, easy shot almost straight into the side pocket, try to put the cue ball on each diamond you can get to without touching a cushion. Here is Joe Waldron's description of it: http://billiards.colostate.edu/PBReview/CBControl1.htm
for some reason there is no photo in the link page
i assume its the set up in the video from dr dave and the diagram that you bob so kindly pmed me in the past