helloo!
I have similar stats but started with smaller boobs just over 8 stone 5″3 size 6-8 dress size.
I had 255cc antomicals [260 cui size] and the cc depend on your breast width not just projection.
so you started with a B cup – 340 may not be much if you have wider boobs to start off with and maybe it has been suggested 340 in a lower profile but bigger width?
so for example an implant of higher projection could be smaller in width but look the same as a larger size because it sticks out more then width wise if that makes any sense at all?!
A smaller frame person like myself could look proportionally the same as someone who was taller/bigger with bigger implants but need less cc amounts to get the same ‘look’