Not sure if this was clearly already talked about before, but leaving aside how they pass the sizes, I still see something that I don't think is a coincidence, or pleasing the customer fact.

Sizes differ in only 2 basic sizes. Why? Why not in all? Why just in those two (teacup & giant)?

Things like that make me wonder and i try to find a reason for it. Knowing that the Meeroo-Creators are puzzle-lovers, I would guess something is hinting there.

One thing that comes quick in mind for me is the giant size and its similarities to elephants. There is two types of elephants (asian & african). They differ in size. So maybe it is not just a "happy-factor" that you got a 14 giant, but also a hint for its direction of history of its kind. Maybe you get even better chances when you split them up like this, combined with the rest factors of your strategy.

The tree has the African elephant diverging from both the Asian elephant and the mammoth about 7.6 million years ago. Then, at 6.7 million years ago, the Asian elephant and the mammoth also go their separate ways.