By this question I mean: Why is it important to start weights at a percentage of a number that is a lot less than your true 1RM, such as in 5/3/1? The reason why I ask this is because in 5/3/1 there is a deload week every month, and while you still technically do the lifts, you are supposed to do it a a very low % and only do 5 reps.
So essentially, during the deload week you are not really working your muscles at all. On top of that, you only do each major lift 1 time a week, meaning that on the first week after your deload week, it as been a full 14 days since the last time you lifted strenuously for that lift. FINALLY to my point: being that on 5/3/1 you have a 14 full days where you do not train your major lift with any effort, aren't you almost "restarting"?
And because of this, wouldn't it be then necessary to start light all over again? For example, If you can take 14 days off from doing any heavy deadlifting, and then still jump right into 85% of your 1RM without issues, then why do you have to start with a 1RM so much lower than our true 1RM when starting a new program or resetting?