Astonishing as it may be to hear "performances" by famous pianists and composers on the reproducing pianos, it must be kept in mind that the "expression" (i.e. dynamics) were all added later, that is, after the pianist recorded the roll, to a special "coding" channel on the margins of the piano roll. We have no way of knowing whether this was done by the original player or by a piano roll editor. So these recordings may represent the original pianist's intentions in the area of tempo and timing, but not necessarily as regards dynamics.