Boys' cashmere half-zip sweater

I purchased both an XXS (size 2-3) and XS (size 4-5) for my newly 3 & 5 year old boys, who both run true to their size. Quality wise, these sweaters are gorgeous and the cashmere is so, so soft. But size wise, I'd definitely say the XXS runs small and is more for a size 2, while the XS leans more towards a size 5. FYI, the XXS sleeves are 3" shorter and the body is 2" shorter, than the XS (see attached picture). Will size up on the XXS and know I'll get more time for him to wear. Otherwise a beautiful sweater and gorgeous colors.