A call to setRowSumsRight(false) on HSSFSheet does not work, when the column group is expanded the column to collaps the group staxs on the right. A call to setAlternativeFormula(false) moves the column to the left as desired by the call to setRowSumsRight(false).
I confirm this behavior: setAlternativeFormula seems to do what setRowSumsRight would be expected to do, and this last one doesn't seem to do anything. However I don't know what setAlternativeFormula should do so maybe the bits are just reversed…