Multiple points vs Single point test in View Analysis

Hi, I have confusion about the result of ptIsVisible and average view in View Analysis tool.
As I know, If we analyze the multiple points, the result of which the highest visible point can be known from the output of ‘ptIsVisible’.
Then, with the same points, I checked one by one of the point (it means the input is a single point), and the average view of visible point show that the highest visible point is different with the result when I input the point test as multiple points.

For example, I had tested three viewpoints (Point 0,1,2) and the result shows that the highest percentage of a visible point is ‘Point 0’, when all three points are tested simultaneously.
Next, I tested each point and the result of the highest percentage of a visible point is ‘Point 1’.
The input of points and their location are same.

Here, I attached the file.
buildings.3dm (53.3 KB) (773.8 KB)