A+2 is also 原味, same taste as A+1. But I found that A+1 and 2 are quite sweet.
A+3 is vanila taste.
My bb had A+1 until 1 year old, then A+2 from 1 year old to 1 year 4 months. Then changed to ''Sum Wing Big Boy'' afterwards. Now he is 21 months and still is happy with it.
I was also afraid that my bb wouldn't like A+3 (vanila taste), so I changed to ''Sum Wing Big Boy'' for him, which is 鮮奶味, not as sweet as A+1 or 2.