This is what I don't get.
Leah and Alice have average proportions. The average breast size is 36C whch is quite large.
Karina is similar to me and we're small compared to the average. We arer nowhere near the normal size. 40 or 50 years ago we were bit proportions have increased worldwide.
I'll try to explain. First thing, bra size is hardly appropriate in this comparison. These few measurements say nothing about proportions, body type, complexion and so on.
Normal healthy proportins define by body type, I speak about ectomorph, endomorph and mesomorth (was forced to google it, in Russia we have sligthly different system). Alice and Leah have the same body type, Melody is close to them. I would say that they're wide-skeleton mesomorphs (there's no such thing in American classification and I cannot find proper translation). Karina looks like normal mesomorph, just a normal girl with average height, right diet and not much physical exercises.
The problem is girls beside Karina have T&A more than they should for their body type. It's possible but with that "assets" they inescapably will be fat. But thay are not. At first I thought it was dev's style of modeling but then there was Karina.
Considering bra size. Not an expert in these strange numbers and letters so I asked my wife. She has bra size something about 36C (well, 85C in Russian/international standards). If she would lose weight numbers in bra size will change but letter will be the sime. Average is some-numbers-B, 36C is totally above average.