Could you give an example or some more detail?
The way I understand it you want it so if you print the first and last pages of your document, then placed them on the desk in front of you with the top edges of the paper aligned, and held a ruler horizontally under any line of text on the first page, it would also line up directly underneath a line on the last page. Is that correct?
This thread is about multi-column documents but it could have some useful information for this topic too: