Hi MBA-Aspirant,
I can't give you 100% suitable guidance to your case but maybe tell a story about my journey, as I deferred my application as well.
After I did not get into my target schools last year, I decided to not take my Option B and re-apply this year (including redoing the GMAT...). It has been a good experience, because you already know how to do it and the process is a lot more efficient.
This time I didn't get into my dream school either, but could find peace in having tried anything I could (and getting an almost full-ride).
So if you are unsure and believe you can make it to M7 (GMAT is on par for that), I would definitely try again next year. It's a once-in-a-lifetime opportunity

PS 1: Currently working at an MBB, I think Tepper is also not a target school, making your chances quite slim...
PS 2: Pittsburgh...