Can't give you advice there - I haven't read your current piece.
However I will say, you've started four drafts for this comp (that I know of). Now you're thinking of starting a new story. If you're not "really sold" on the story, why bother having it published? It seems to me like you don't have a story written which you fully believe in and are happy with. If you submit this story, I think something will always be missing from it. You yourself said you're "not really sold on this story." It's frustrating, but why not sit back and take a beat? You've written multiple stories with new ideas seemingly non-stop shortly after this comp opened. There's still time to enter. Maybe an idea will come to you when you're watering a plant, etc.
For me, the first few days after the comp opened, all of my thoughts were focused on a possible idea and I kept coming up with nothing. I finally relaxed when I stopped thinking of the comp. If an idea comes to me or I get inspired by something, great. If not, I'll just have to sit this one out.
*I truly hope you didn't find my advice harsh. I was telling you my sincere, honest thoughts.