Why my Breast Still Look Small After 410 & 420 Cc HP Saline Under the Muscles? (photo)

I had my op sept 13, I'm 3 days post op and find them small. At my ps when I tried the 400 cc I found it was too big, but I decided to go a little bigger to not fall in the category of those who wishes to have gone bigger. My ps put 410 cc in the right breast and 420 in the left. I look bigger when i was breasfeeding. Why I looked bigger with the sizer than the actual implant which is bigger? And they say you look bigger at the beginning it's that mean they will look smaller? why they're small?