Just curious.... what was the fare you paid and are you doing this to maintain status or shooting for 1P or 1K?

Your time is the fastest I have heard so far. ^ I believe you were benefited from ( in addition to weather):

1. slow air traffic period in air and airport
2. red-eye departure time and early moring arrival and departure time.

Try SFO-JFK or SFO-IAD next time as there are multiple daily departure each direction, and you could see yourself beating the 13-hour mark.

Your story ranks right up there with the story (I heard on FT) about someone did US-SIN-US roundtrip back-to-back.