I had just lowered my 4.8iS on Sunday using DIS. In my case, the rear right sits about an inch higher. I measured from center of the wheel to the edge of the wheel well. GT1/DIS will ask you to enter measurement for each corner and it will do the calibration base on that.
Using TwinPoppa's guide, I enter 707mm (stock sport front with 20" wheels) + 25mm (I want to lower 1 inch all-around) = 732mm for the fronts. For the rear left, it's 709mm + 25mm = 734mm. Since the rear right is 1" higher, I entered 709mm + 50mm (2" lowered) = 759mm.
Now they are even 1" lowered all-around. Remember you have to be on level ground.
I send you a PM with my number if you need help.

__________________

00 E39 DINAN S1 //M5 (82k miles)
06 E53 DINAN 4.8iS, born 2/18/2006 (126k miles) http://www.xoutpost.com/bmw-sav-foru...s-my-dslr.html
90 Straman Z32 TwinTurbo Convertible, (1 of 44 ever made) 5 speed, 444rwhp/451rwtq
01 360 Novitec Spider F1 (26k miles)