I never noticed that the poco ritenuto was missing from the Joseffy edition published by Schirmer, so thanks for point that out.
Unfortunately, there are no assurances that details like dynamics, articulations, etc. are original unless one is using an urtext edition. Otherwise editors generally take some editorial license, and some are far more heavy-handed than others.
Most publishers are prone to the occasional typographical error, too, and Schirmer is no exception. Still, the engraving of most Schirmer scores is clear and spacious—and Joseffy’s editions of Chopin have the most consistently useful fingerings for my own hands of any I’ve ever seen.