When an AGV performs its lookahead allocation, it must provide enough time to come to a stop if the allocation fails. This is why AGVs will allocate ahead when they "pre-arrive" at a control point, instead of when they are fully at the control point. Max speed and deceleration can affect this "pre-arrival" time.
Say, for example, an AGV has allocated and is traveling to CP1, and wants to continue to CP2. If, when it arrives at CP1, it cannot allocate CP2 (CP2 is allocated by another AGV), it must decelerate to stop at CP1. Let's say, for example, it is traveling at 1 m/s, with a deceleration of 1 m/s/s. Here it will travel 0.5 meters in decelerating to stop. Thus it must allocate ahead to CP2 when it is 0.5 meters short of CP1. By doing this, if it fails to allocate ahead to CP2, it can still decelerate to stop before passing CP1.
The deceleration you set on an AGV will significantly affect this "pre-arrival" distance. Decelerations that are very small will cause AGVs to perform their lookahead allocations long before they arrive at control points. This is by design.
In your case, you've set the max speed to 10 with deceleration 1. The AGV is able to hit about 6 m/s before it needs to decelerate to stop at CP12. In decelerating to a stop, it would take 6 seconds, and travel ~6*3 = 18 meters. Thus it needs to allocate ahead about 18 meters before it arrives at CP12.
