the actual move offset does not match ipad resolution pixel

[memetea]

I tested on ipad mini 5. The resolution is 2048*1536.
1、When I set initial x to 0 and call move to increment x by 10 every time. I found that x incremented by about 1300 totally when the cursor reaches the edge of screen in landscape view. That's far away from 2048.
2、When changing increment step from 10 to 50. The final movement along x axis is only about 660.
3、When calling simpleMove(0,0) #19 and then moveTo(0, 100, 1.0, 0, 0, 0) the cursor moves along y by y1. When calling simpleMove(0,0) and followed by moveTo(100, 100, 1.0, 0, 0,0) the cursor moves along y by y2. I found that y1 is larger than y2.

I don't understand why the above experiments happen. Is there any explaination?
Thanks in advance.

[memetea]

It seems there are acceleration that cause the logical movement does not equal to physical movement.
Moving 100 three times and moving 300 once along x direction does not go to the same physical point.