Yeah it's just time and distance variation between balls released at the same velocity from two different distances (12 inches apart). One will get there ahead of the other, obviously. The one closer to the target looks faster because you have less time to swing at it. A ball travelling from 54 feet away from a target must travel 3 mph faster to arrive at the same time as the ball traveling from 53 feet away from a target.
In general, if you can cut down the pitching distance before you let go of the ball, you have an advantage...just like that guy who hops forward with his pivot foot before foot strike. He's getting about 4.5 mph advantage (due to his 18" hop) over someone else throwing the exact same velocity.