I thought a visual aid might be helpful. This is the first floor of my house. You can click on the picture for a bigger view. I'm not sure why there needed to be an entryway in the kitchen once upon a time, but maybe it was to add an airlock. I think the room that I use as a pantry was always there, though when I moved in, it was more of a mudroom.
In any case, when the entryway was removed, the load-bearing wall (the "bad" wall) was apparently not properly reinforced. The bad wall does continue all the way to the front wall next to the front door, with an archway through to the dining room. Same on the livingroom side. So the break in the load-bearing wall is only there in the kitchen, and it is directly above that that the walls are so cracked upstairs. If the house is sagging there, it stands to reason the load-bearing wall is going to sag too.
The blue square is the masonry column in the basement the structural engineer believes is settling. This is also a reasonable theory, but John K.'s 4ft. level shows everything on the straight and narrow until you get upstairs