Treadmill hills

I start at 7 mph and an incline of 2% and then every half mile I increase the speed by .2 and then incline by .5 and then at the top, I decrease by .2/.5 every half mile. When I ran this workout two weeks ago I only did 1/2 mile at 8.2/5% and then started decreasing. Today I did a mile at 8.2/5%, but I did have to stop once. 7 miles total.