That’s a high ass box.
As the previous poster said, you’re not flexible enough to get that low. if you are going to pull from that position, try a snatch grip maybe, or a lower box.
Hip flexors, and your entire posterior chain need to be flexible as hell to pull from that kind of height.
Personally pulling from a deficit greater than 4-6 inches fucks up my form and later on i can’t translate the gains into anything fucking useful for a while.
I’m stronger, dont get me wrong. Like the weights feel lighter, but i’m so out of groove with my regular deadlift, I need like 2-3 weeks to realize any sort of strength transfer.
Damn 10 inches. you must have monkey arms man.