Confused on what size to go witj breast augmentation-been told 2 different things

Hi I’m about 167cm high and 54kg. I’m about a 10a at the moment and am Wanting a full round look. One dr told me no bigger then 375cc as I am quite small framed. Another doctor was happy to put 400cc in me, they didn’t look that different are all cc’s the same? Just worried the 400cc will be too big. Does anyone else have same height and weight roughly as me? Why did you get