Breast size should be fully established before and going breast augmentation.
This is a complaint I hear much too often. There good sizing systems which should make unexpected volume changes rare. I doubt adding 75 mL is going to be worth going through another operation.
Will 75 mL make a difference?
I'm sorry for your dilemma. Adding just 75 mL to an existing implant will not be a significant difference that one can readily see. I suggest for significant difference you need at least 150 mL
Adding volume to implant
A jump in cup size is at least 175cc so adding 75cc is not a lot of volume. You are also likely still somewhat swollen if your surgery was only 15 days ago so you may look even smaller one that settles out over time.
Adding 75 cc to a saline filled implant
Thanks for your question and post. Adding 75cc will increase your cup size by about 1/3. This is only an estimate.