You should be able to hit your TM for several reps easily.
That means you should be able to hit your 1+ “AMRAP” for >5 reps.
This is all explained in the books. Deloading 10% is not part of any 5/3/1 program that I am aware of.
Jim doesn’t have an official app so whatever you are using is not actually 5/3/1 which may explain your confusion.