If you look at her profile you'll notice that her bust is 85 cm and she's only 156 cm tall, E-cup from the source:
AI-chan's big breasts are quite noticeable if you take a good look, her measurements are the same as Matou Sakura/BB. But I keep seeing people using a model with a Miku body, which has small ones.
I honestly find a bit baffling that so many people see her losing 3 cup sizes when she takes off her vest and don't think it's odd. So I made this thread to bring a bit of attention to this matter.
The mentioned Miku chimera model is also missing AI's detached sleeves and thigh-high boots. There's this model with bigger breasts and all of her clothes:
However, her butt isn't as nice and her nipples look a bit simple. If anyone wants to take on the challenge of making a definitive AI-chan model, that'd be great too. This is what she officially looks like under her clothes: