<p>Generally speaking, I think a third letter from someone unrelated to your school is better. Penn asks for two letters from your school. I’m assuming Penn is convinced that’s enough. A third letter from someone at your school sounds a bit like overkill to me. However, a third letter from an employer offers a completely different perspective, which can be helpful. Lastly, I wouldn’t do a third letter just to do one. I’d offer a third one only if it was amazing. Again, the point isn’t just to submit another letter. It’s to offer a different perspective that shows how great you are. I’d recommend it only for those students who had great work experience, which is rare. You have that kind of work experience. </p>
<p>Again, good luck.</p>