How Did I Only Go Down 1 Cup Size After my Breast Reduction?

Without a picture it's difficult to decide how much breast tissue should have been removed. The amount you state is relatively modest as breast reductions go particularly with extreme breast hypertrophy. After the swelling has subsided you might need to be re-reduced.

It is very difficult to predict what cup size you will be after a breast reduction.  Bra sizing can vary significantly depending on the bra, etc.  The other issue is post-operative swelling.  It may take several months for your breasts to settle and for the swelling to go down.  I would base your results on how you feel (does your back feel better?) and on how your breasts look.  Good luck!

If you were indeed an F cup before your procedure and only had a 400 gram reduction the amount is on the modest size by reduction standards. The numbers just might be what they are.

Really have no factual basis to answer this question without photographs.  You did not mention how long it has been since your surgery.  If you were a FF  I would suspect that more than 400 grams would be removed but your surgeon is in the best position to understand your anatomy and make surgical judgement in your best interest.