According to the article, Elder Battalion becomes worse the more you progress into the game. While this is true for the most part, by the point you reach 700+ buildings with most building types, Elder Battalion becomes better.
CPS with Elder Battalion is higher than with Breath of Milk at this point.
Breath of Milk has a lower CPS contribution than Elder Battalion here.
Grandma CPS without Elder Battalion. On their own, they contribute to a measly 1% here.
Grandma CPS WITH Elder Battalion. They contribute to a whopping 60.9% here.