It depends on the content of each essay, but I think it's always good if you can cut down on what you're asking the admissions office to read. If you cover your diversity factors in your PS, you don't need to write a separate DS.
This is a link to a 3 minute video about a Georgetown Law grad who makes $40,000 per year and lives with his Mom. It's worth watching if you are considering any law debt. It could save your life, financially. https://www.youtube.com/watch?v=UJ1_g3LvdR0
Not surprised by Georgetown nor Harvard. Bit surprised by Berkeley. Extremely surprised by Columbia: I had a bet with a buddy that Columbia would jump to 3 and tie Harvard. Looks like I owe him a beer.