Answer (1 of 4): Well, I don't know how this sister sizes ( in relation like sister companies etc,,) ever became as you describe..There is nothing remotely close to each of those sizes. Mathematically and according to any standardized charts ..Remember one very important rule in life .Mathematics
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Sister Sizes: The Bra Secret Every Person Should Know – Sister Sizes & Equivalent Bra Size Chart – ThirdLove
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