All I can think of, is at these weights, it probably makes sense to chuck out the percentages. For the lack of a better expression, the "feel" of 90% for a 685 lbs max would be considerably different than for a 385 lbs max. At least that's what common sense tells me. So, as you approach the rarefied strength levels, may be its time to chuck out %ages.
Also, I find Chaos and Pain's approach interesting. He is a big time advocate of hard work, but pays a lot of respect to the deads. Once read in his posts that after you start pulling big numbers regularly on the deads, heavy pulling every week can be a back wrecker. Therefore, the idea was to cut the deadlifting frequency, add in rack pulls and increase the squatting volume.