OK, I answered my own question about deadlifts from box by googling and finding an old post by Lisa. Thank you, Lisa, for helping all of us!!
I was confusing deadlifts and squats... My deadlift form is OK with my hips higher than my knees in the start position. My back stays straight and I don't have any unusual soreness, so I guess it's OK. BTW, in case you missed it, I deadlifted 85# yesterday! I'm getting close to my BW!!