on MY2017: once it's open to desired height, push and hold the liftgate close button (on bottom of liftgate) for about 3 seconds until it beeps. This sets the opening height. Not sure if it's like this on all years but it may help.
NB: on my car even after programming the height to max setting (pushing up on liftgate and setting the height) it still does not open to the actual max height. It seems there's a maximum open height which is about an inch or two lower than the maximum height that you can manually open it to.