When i bench 400 i could get 3 reps with 365, while my freind could bench 365 x 5 before he did 400.
On 80% max i could get around 7 reps, alot of guys make this mistake, when working percentages to figure power cycle they figure their 1rmhigher in an attempt to increase lift faster , has opposite effects missing lifts detrimental to lifting cycle.
Also the shorter range of motion the more reps with 80%.
Example take two guys who can pull 500 80%of which is 400.
One is sumo one is conventional puller the coventional puller will get 5to7 reps with 400, the sumo will get 8 to 10 reps with 400.
The sumo pull is generally a shorter range of motion and less time under weight per rep.