Dear @haejin, thank you for your analysis.
Let me express my own opinion about the index. As it seems to me, the downward movement will be below the point C indicated by you, by about 1 figure, that is, somewhere in the area of 2 400. Although I agree that it is not fundamentally and not critical.
But ... then, after moving up, it is possible to further reduce the index to the next level around 2 110.
If you are interested, I can attach graphs as arguments.
I'm sorry if my comment was impertinent.