Is there that much difference between HP 425cc and 330cc?

150cc to 200cc is about a cup size so going 100cc smaller can make somewhat of a difference in your result.   Although you both decided upon a 425cc implant, perhaps when he went to place them, your body couldn't accommodate them so he had to go with a smaller implant.  No one will know but your surgeon so go see him for a follow up visit, discuss your concerns and go from there.  ac

In general there is not that much difference when you are talking about this volume change. You could expect maybe 0.5 cm or less of a projection difference and minimal changes in the base diameter of the implant as well as the height. It is impossible for me to know without knowing which implants you are speaking of. There are books that have the dimensions for every single implant that our implant companies give us. We use them to select the device that best fits a patients body. Just ask your surgeon to review those numbers with you and you will see there is not much difference to speak of when you are talking about this small of a volume change.

You will likely be best off addressing your concerns/questions with your plastic surgeon. Generally speaking, the difference in roughly 100 cc of breast implant volume can create a  significant different outcome,  for patients with your body type. Best wishes.