You said: "Betty,
When you do a Ahnentafel report it will do both lines by default, so all you need to do is one."
That depends on the situation. I have approx 30 paternal first cousins and 30 maternal first cousins. Each of my parents had 7 siblings.
If you are going to make one book to give to both maternal and paternal cousins, it would be best to give each side their "own" ahnentafel. Of course, there might be a benefit to two books in that case, as well.
Also, I have one side that is New England with 150 immigrant lines to America back to 1630. My other side is German and Scots-Irish, only back to the Revolution. One side so dominates such an ahnentafel and buries the German and Scots-Irish side as to make separate ahnentfels easiser to navigate.
Of course, in the particular case of the New England ancestry, it would be better if FTM would do a "line-by-line ancestry, the way it is usually presented in most books, rather than an ahnentafel presentation. This is a separate chapter showing a direct-line register descendant register report for just one line. My New England ancestry report would have 150 chapters and 150 direct line descendant register report in this scheme. The Line-by-line, separate chapter for each line, format is much easier to follow than fumbling through ahnentafel numbers. I make this request each year - please join me.