I just voted to approve this edit because it does clarify the point made by the answer, however I think it takes it beyond the knowledge or intent of the original poster and am still not sure if approving was the best way to go.
In this instance, there is a good case for the editor to have written their own answer, because it is quite far ahead of the original in terms of description, detail, and possibly knowledge of the OP.
As regards your review, I think approving was the correct course of action here. We are left with an answer which was better than the original. It doesn't conflict with the original post, it augments it, so as an overall win for the site, it's pretty good.