Not sure if it is AP2 only. I haven't used on non AP2. If I set my offset at +5, and then pull the stalk and hold, it will set cruise to +5. Let's say I am cruising at 65 with the offset limit at +5 on a 60 mph road. I enter a 50 posted zone that is recognized. The car will automatically reduce to 55. When the posted limit increases again. The car automatically increases to the original set speed of 65. So, I think there is one limitation. The car will never exceed the original cruise setting. So, set it at the maximum speed you will be traveling. I have used this on hwys and aux roads.