I need help understanding the use of credits

I uderstand that it takes one credit to create the text to image. However often the image needs editing to make it acceptable. The image on the left was the original AI created image . You can see that there are some areas that need editing to make it look realistic. Each of these areas need one edit with the nose and mougth area needing two edits. The total cost to make ausuable ilmage would have been 6 credits. Is that correct? Oh the cat's back and the wall took several tries but I could have probably fixed those with a photo editing program.