You are paying this fee according to this clause in the TERMS OF AGREEMENT:
Revisions: In the unlikely event that you are not satisfied with the artwork I provide, I would be glad to make small revisions for free. You will be given the opportunity to request revisions before completion. If I determine that the revision would require a re-draw of a large portion of the image, I will direct you to the option of purchasing a revision at $50/revision. If any revision is due to my mistake or misrepresentation, it will be free. I reserve the right to determine reasons for revisions, but I will gladly hear your reasoning as well. (I always try to make a determination in your favor!) * *Please allow 2 weeks extra creation time for each revision. If you are still unsatisfied, I am not at liberty to provide a full refund, as the work has already been done.