If I may take a shot at this, I believe @Ed Compton is referring to this chartOh maybe because we have a “try dope” and then and actual, which is our way of saying you can adjust from the math plus or minus to hit water line ?
But I didn’t understand the question?
@Ed Compton if my assumption is correct it’s simply because this chart covers a wide range of bullets and ammunition combinations. As you get further out there are more variations resulting in more possibilities which requires the use of more rows. That’s all.