What you just described should never, ever be done by anyone. You've got your terminology all messed up too.
Deloading would involve a decrease in intensity and volume for a short period of time to either be restorative after a hard training cycle or supercompensative before a competition.
What you are describing is negatives, where you over exaggerate the eccentric (lowering) portion of the lift. Deadlifts suck enough already. Just thinking about doing negative deadlifts made every part of both my hamstrings rupture and and then projectile vomit them all over my keyboard. So, thanks for that.
Man, I remember one time reading an article that suggested putting a bar in a rack UNDER the support pins, then when you did the deadlift the bar was physically stopped at just above knee level. The idea was that it forced you to get used to "grinding" through the sticking point. STUPIDEST thing I ever did.
And yeah, "deloading" means take a week to lift at 50% or less of your 1RM for reps well before failure. Keeps the body healthy and lets your CNS recover.
Try to imagine this. Get in a squat rack. Put the safety pins at a little over knee height like you're going to do a rack lockout. Now, put the bar on the floor, UNDER the pins. Put some weight on it, and pull it so it hits the underside of the two bars. Once there, keep on trying to pull anyway. Idea being, like I said, to teach yourself to keep on a-pullin' even when the bar isn't a-movin'. It was in an article here on T-Mag some time ago.
i could be wrong, but i think you're looking for the reason people let the bar settle at the bottom of the deadlift, reason being to develop power from the floor by moving weight from a deadstop, hence deadlift.
isotonic-isometric deadlift, this technique can be used on a lot of lifts- ive tried it with bench, dead, and squat- the point is to exert maximum intensity on an immovable load, but moving the bar a short distance before hitting that point (the pins). I think I read about them on the starting strength site in an article by bill starr. I havnt kept them in my regular routine but did like them when i used them, just something different.