why not add a subsection for this like everything else, instead of these four totally unexplained editable numbers underneath the graph? i’m trying to think how the UX of this can be improved.

Agreed to Adriaan, I probably wouldn't intuit what these inputs will do.

If we want a strong visual indication, they'd have to be arranged at the axes:

However, that would cost a bit of space on the x axis, so I'm not sure if that's worth it. Otherwise, adding sections will probably do.