According to us, the mark getting increasingly shorter in FE and EE – in EE the mark is actually a long accent – resulted from inaccuracies in the recreation of the respective bases ([FC] and FE). It could have also been Fontana committing an inaccuracy in [FC]. However, it must be said that a possible difference in significance between these marks is marginal, since in the Chopinesque notation a 
hairpin not preceded by a 
mark means an 'extended long accent', which is to be interpreted as a long accent and diminuendo.
Compare the passage in the sources »
category imprint: Differences between sources
issues: Inaccuracies in FE, EE inaccuracies
notation: Pitch