>>12527912>Regular elf = A to D>HiElf = DFC to C
Consider the following:
► Elves are a very long-lived race - they literally have all the time in the world, compared to more standard races like humans, which generally means they are more indolent (or lackadaisical slothful or lazy, if you prefer). This gives them more time to also generate more fat than muscle, considering their lifestyle and diets, and given the fact that when you exercise less, your body starts to deteriorate the muscle tissue instead of burning away the fat, so they would have larger breast sizes on average, even for the more athletic characters.
► Humans are a more slovenly, yet also more industrious, race - their appetites for food are second only to their appetites for technological and architectural advancement. Plus the common fact that they have a lifespan of at most 100 years, they hustle and bustle as much as they can, working hard to finish projects and be in peak physical shape to ward off aggressors. From person to person, they are more likely to work off the accumulated fat, so they have more variance in their females' chest sizes yet are prone to also having smaller chests on average.
► Given the previous two facts, you can imagine that half-elves would have have traits from both parent races, being both graced in terms of the elves' longevity but cursed by the desires of man - namely the appetites of their human ancestors. But they are also taught about the diligence of their human parents, leading to slightly less varied, but somewhat larger, chest sizes among the women.
So it's more like:
Elves: B - D
Half-elves: A - B/C
Humans: DFC - DD(+)