Hi Angélique,
The "subtract a size" is the greatest urban myth of all time. Just think about it. If you're great grandmother was a C cup, you're mother would be an A and any future generations wouldn't have breasts. My mother is a B and I'm a D, and my daughter is a EE, god bless her.
Just make sure you have a good Endo, who knows how to look after them, and feed you with the right stuff.
Speak to you as soon as I have a cuppa with the girls.
Huggs
Catherine