It isn’t a discrepancy. As a writer I can tell you that minor differences in details like this will pop up when a story is told more than once, even by the person to whom it happened. Paul may not have known the others fell down with him in the first account since he went blind and so probably didn’t see them fall too. They may have told him that they all had had fallen later on, so he included it in this later relating of it. Also, people will have different experiences than others at the same event, but not realize it. This is not uncommon even in news stories today.
