Just something i do to work the bottom of my dead, especially for lower %'s:
for my 5x3x1, i have my DL weight set at 465. Jim's 90% puts that at about 420 for me to base my %'s for the cycle. When i do my boring but big, i work at about 55% of 420, which is around 230. To emphasize my bottom at this weight, i use 25 lb. plates instead of 45's.
The difference in the physical size of the plates forces me to pull from about 4-6'' lower than i typically do. This gets me deeper, emphasizes my bottom, and gets good work for the sets of BBB. As Jim says, when you do the BBB, the 5x10 is to emphasize the muscle in the movement.
This may not work for everyone, especially guys with super strong deads, but for me, i can really tell the next day after i do these.
*i do not do these every week. 10 reps are a lot of DL's at any %. I will throw this in every other cycle just to push myself. Besides that, i use the 25's for warming up into working sets.