Feel free to correct me if I'm way off, but I see working on weakness in this portion of the deadlift plane like working on a bench weakness that's not even in the bench groove. Does that make sense? You're never realistically going to be in a postion (that I can think of) where you will be traveling through that plane, with that form, and with that speed. So I'm not sure it's all that beneficial to guage your overall deadlift strength/weakness by this move. If you reach a one rep max on a deadlift from the floor, you will KNOW your sticking point. You will either freeze in the middle, not get it off the floor, or fail to lock it out. To me, this is a better indicator of strength and weakness, and what needs to be worked on.