I'm not sure I ever read anywhere that its more beneficial to write a different statement for each school. How would you ever have time to write 14 good (and different) statements? You'd have to start like 2 years before you want to apply! I know mine took me months to perfect! And how is what you're going to tell one school so drastically different than another? Most schools ask you to talk about why you want to be in a lawyer and what has prepared you for the study of law. You've only had one life, so how do you have 14 different stories to tell?
However, I do think its important to have a portion of your statement that is tailored to the school. It shows interest and that you've done your research. This is why I changed the last 1-2 paragraphs of each statement, this is where I explained why I wanted to go to that particular school. I focused on the location and why I wanted to be there, what programs the school had I was interested in, etc.
I think it would be a waste of time to write 14 completely different statements. I wrote one and then changed the last couple of paragraphs to reflect my interest in each school. Then for the one school that had a more specific topic I wrote a new statement. It took me long enough to write one statement and perfect it, then several days for each school to adjust the end of the statement to reflect my feelings about the school. I can't imagine having enough time to write 14 completely different statements and I certainly see no need for it.