Here is the thing:
In the situation that the anchors are separated with value (0, 0) (0.5, 0.5), the anchored position of the red rectangle should be the vector(the yellow arrow) from the center of the anchor rect, which is (-125, -125), to the pivot position(100, -50), the result should be (225, 75), and so it is.
But if I move the pivot to the bottom (100, -100), I think the anchored position should be (225, 25), but in fact, it is (225, 150)(the green arrow). Do I misunderstand anything or is there anything else that should be considered when the pivot is not at the center?