YP? What makes you think Vandy YPs? Nothing on LSN gives any indication of this. Everybody who was WLed with LSATs of 169+ had relatively bad GPAs (two 170+ WLs were 3.57/3.63 and hardly seem to indicate a pattern). Everybody with even a decent GPA was accepted with respectable or lots of money.
I wouldn't bother with an extra addendum. Just put together a good application that shows you care.
Also, re: YP, his LSAT is not going to be above the 75th compared to the new 1Ls. His LSAT will also likely be the new median. Schools that YP don't YP median candidates. They're the school's target/reaches with $$$.
Other comments: Rusky doesn't seem to know anything. As observationalist pointed out, the people working in Nashville have ties to the area. Unless she just simply lacks clarity, either school does not get you a job there easily.
If, on the other hand, you thought you might want to work more nationally, then a T14 would probably be a better bet. Vandy can get you national biglaw if you're near top of the class, but that's tough to achieve at a place like Vandy, where everyone's pretty bright and studious. The T14 will give you national options even if you're average.
All indicators point to median (presumably what you mean by average) kids going nationally just fine. They have to. There aren't many jobs in the region.
I wish people would cut this T14 nonsense out.
I suppose you know I'm wrong from experience?
Well, allow me to clarify that my comment is actually from experience of interviewing with Nashville firms as a T14 student. While I've never lived in Nashville, I assure you I had no problems getting offers at Nashville firms, even though I got my first interviews through cold calls and a mail campaign rather than through OCI. Had a similar experience in Texas.
At the end of the day, regional ties matter far less to firms than pedigree. They all want prestigious law schools listed in their attorney bios, and if a candidate with no regional ties but a T14 degree is reasonably convincing that he is serious about staying in Nashville, he will have no trouble getting a job there.
Before you point out how few lawyers from T14's work in Nashville firms, consider that these statistics are not telling of how many T14 candidates were actually given offers. Obviously, there are fewer T14 candidates that want to work in Nashville, because it is a secondary market, but that does not mean that they are having trouble getting jobs there if they want them.