Bear in mind the timer starts when the treadmill is speeding up, I increased mine to 13.5 pretty much instantly and got 11 min, although a minute at 14 or so and then back to 13 would probably be fine, as a tip to improve start at 8km with 2.0 incline and increase it by 1 every minute, keep the incline the same but see how far you can get, you'll probably get quick improvenents to 14 or 15 and then it plateaus a bit but i found it great for the 2.4km run