I'm going to go off of NARP's ridership data (which differs a little from the Amtrak ridership report data), but 5 of your top 9 ridership pairs and 4 of your top 9 revenue pairs fall under that category. Setting aside the Hoosier State-supplemented stops in Indiana, Charlottesville and Cincinnati both send quite a few folks through to Chicago (ridership to Chicago is right behind ridership to Atlanta for CVS, which is saying something considering that ATL has the Crescent running daily versus the Cardinal going 3x weekly). With that aside, the stops in WV switch back and forth between WAS and CHI as their #1 destination (HUN and WSS have WAS, HIN and CHW have CHI). The turnover in CVS has actually been pretty stunning every time I've seen it.
That was my suspicion on riders CVS west <> CHI. But it is somewhat surprising the ATL comparison. Have done ATL <> CVS <> Cardinal going west. Had quite a few connecting passengers waiting with us at CVS. The long wait at CVS enable views of the university and downtown on the trolley.