I have never personally used this shuttle, but it seems to me that it's utility is really in the opposite direction...from A to E. The reverse route would require you to complete your immigration formalities, then go back up to clear TSA security at E. Then you have whatever wait there is for the next bus and the 10-15 minute bus rude depending on which flights are being pushed back at C and B. I am not sure that would be better than the 10+ minute hike through Central Parking to A.